onomatopoeia
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C2 noun /ˌɒn.əˌmæt.əˈpiː.ə/

onomatopoeia

オノマトペ
Meaning
The formation of a word from a sound associated with what is named.
Example
The word 'buzz' is an example of onomatopoeia.
'バズ'という言葉はオノマトペの一例です。
C1 verb /ˌaʊtˈduː/

outdo

超える
Meaning
To do better than someone else; to surpass.
Example
She always tries to outdo her classmates in exams.
彼女は試験でクラスメートを常に超えようとします。
C1 noun /ˈɒktɪv/

octave

Meaning
A series of eight musical notes, or the interval between one musical pitch and another with double its frequency.
Example
The singer's voice could easily reach the higher octave.
B1 adjective /ˌoʊvərˈsiːz/

overseas

海外
Meaning
in or to a foreign country across the sea
Example
He went overseas for higher education.
彼は高等教育のために海外に行った。
B2 noun /ˈaʊtˌskɜːrt/

outskirt

郊外
Meaning
the outer edge or border of a town or city
Example
They built a new factory on the outskirts of the city.
彼らは街の郊外に新しい工場を建てました。
C1 noun ˌoʊ.vɚˈɡreɪ.zɪŋ

overgrazing

過剰放牧
Meaning
The practice of allowing livestock to graze to the point of damaging vegetation.
Example
Overgrazing leads to soil erosion and loss of biodiversity.
過剰放牧は土壌の浸食と生物多様性の喪失を引き起こします。
C1 adjective /ˌɒbsəˈliːt/

obsolete

時代遅れ
Meaning
No longer in use or out of date.
Example
Floppy disks are now completely obsolete.
フロッピーディスクは現在完全に時代遅れです。
B2 adverb /ˈaʊtraɪt/

Outright

直接に; 完全に; ためらわずに
Meaning
completely; directly; without reservation or concealment
Example
She rejected the proposal outright.
彼女はその提案を直接拒否した。
C2 noun /ˈoʊ.kəm/

oakum

古いロープの繊維
Meaning
loose fibers obtained by untwisting old ropes, used for caulking ships
Example
The shipbuilders used oakum to seal the gaps in the wooden planks.
船大工たちは木の板の隙間を塞ぐためにオーカムを使いました。
C1 adjective /ˌaʊt ən ˈaʊt/

out-and-out

完全な
Meaning
complete; absolute; used to emphasize something extreme
Example
The speech was an out-and-out lie.
そのスピーチは完全な嘘だった。
B2 verb əbˈzɜːrvd

observed

祝う
Meaning
To celebrate or keep a religious or other festival.
Example
The day is observed annually to raise awareness.
その日は毎年意識を高めるために祝われます。
B2 noun ˈoʊzoʊn dɪˈpliʃən

ozone depletion

オゾン層の減少
Meaning
The reduction in the amount of ozone in the Earth's stratosphere, leading to increased UV radiation.
Example
Ozone depletion increases UV radiation.
オゾン層の減少はUV放射線を増加させます。
C2 noun /oʊˈbeɪsəns/

obeisance

敬意
Meaning
A gesture of respect such as a bow or curtsy.
Example
They bowed in obeisance to the king.
彼らは王に対して敬意を示すためにお辞儀をした。
B2 noun /əˈpoʊ.nənt/

Opponent

対戦相手; ライバル
Meaning
a person who disagrees with or resists a proposal or practice; someone who competes against another
Example
The chess player defeated his strongest opponent.
チェスのプレーヤーは最強の対戦相手を倒した。
C1 noun ˌɒk.sɪˈdeɪ.ʃən

oxidation

酸化
Meaning
A chemical reaction that involves the combination of a substance with oxygen, often causing deterioration.
Example
Oxidation causes metal surfaces to weaken.
酸化は金属表面を弱めます。
C2 noun ˈoʊʃən ˌstrætɪfɪˈkeɪʃən

ocean stratification

海洋の成層
Meaning
The formation of layers in ocean water due to differences in density.
Example
Ocean stratification affects marine biodiversity.
オーシャンストラティフィケーションは海洋生物多様性に影響を与えます。
B1 adverb /əˈkeɪʒənəli/

Occasionally

時々; たまに;
Meaning
sometimes; from time to time; not regularly
Example
I occasionally visit my grandmother on weekends.
私は時々週末に祖母を訪ねます。
B2 noun /ˈɒpəreɪtər/

operator

オペレーター
Meaning
a person who operates equipment, a business, or controls something
Example
The machine operator ensured that everything ran smoothly.
機械オペレーターは、すべてがスムーズに動作することを確認しました。
C2 adjective /ˈɔːrnəri/

ornery

気難しい
Meaning
bad-tempered and combative; stubborn
Example
The ornery old man refused to leave his chair.
その気難しい老人は椅子を離れようとしませんでした。
C1 noun /ˈɔr.ə.kəl/

Oracle

オラクル
Meaning
a person regarded as a source of wise counsel; in ancient times, a priest or priestess acting as a medium
Example
The ancient Greeks consulted the oracle at Delphi.
古代ギリシャ人はデルポイのオラクルに相談しました。
B2 adjective /əˈpəʊzd/

opposed

反対の
Meaning
being against or in disagreement with something
Example
She is strongly opposed to animal testing.
彼女は動物実験に強く反対しています。
B1 noun ˌɔː.ɡən.aɪˈzeɪ.ʃən

organization

組織
Meaning
An organized group of people with a particular purpose, such as a business or government department.
Example
The organization was officially inaugurated in 2024.
その組織は2024年に公式に開設されました。
B2 noun /əbˈdʒek.ʃən/

Objection

異議; 反対; 抗議;
Meaning
an expression of disagreement or disapproval; a reason for disagreeing
Example
The lawyer raised an objection during the trial.
弁護士は裁判中に異議を唱えました。
C1 verb /ˈɒp.tɪ.maɪz/

optimize

最適化する
Meaning
To make the best or most effective use of a situation, opportunity, or resource.
Example
The company is working to optimize its supply chain.
会社はサプライチェーンの最適化に取り組んでいます。
C1 noun /ˈɔr.i.ənt/

Orient

東洋、特に東アジアの国々
Meaning
the East, especially countries of eastern Asia; to determine one's position or direction
Example
Many spices come from the Orient.
多くの香辛料がオリエントから来ています。
C2 adjective /ˌoʊpəˈlɛsənt/

opalescent

オパール色の
Meaning
showing or reflecting a milky, iridescent light like an opal
Example
The opalescent sky glowed with shades of pink and blue.
オパレッセントな空はピンクと青の色合いで輝いていた。
B2 verb /ɒpt/

opt

選ぶ
Meaning
to choose or decide to do something instead of something else
Example
Many students opt to study abroad for better opportunities.
多くの学生がより良い機会のために海外で学ぶことを選択します。
B2 noun/verb /ˈaʊtreɪdʒ/

outrage

憤慨
Meaning
A strong feeling of anger and shock; to arouse anger or shock.
Example
The unfair decision caused public outrage.
不公平な決定が公共の憤慨を引き起こしました。
C2 verb /ˈɑːblɪˌɡeɪt/

obligate

強制する
Meaning
to bind legally or morally; to compel someone to do something
Example
The contract obligates the company to provide timely service.
契約は会社にタイムリーなサービスを提供することを義務付けます。
C1 adjective /ˈaʊt.kɑːst/

Outcast

社会的に排除された人
Meaning
rejected by society; excluded person
Example
He felt like an outcast in his new school.
彼は新しい学校でアウトキャストのように感じていた。
B1 adjective /əˈfɪʃəl/

official

公式
Meaning
relating to or connected with an authority or public office
Example
He is the official spokesperson for the company.
彼は会社の公式なスポークスマンです。
C2 noun ˈɒpjʊləns

opulence

富裕
Meaning
Great wealth or luxuriousness.
Example
The opulence of the mansion was evident in its ornate furnishings.
豪邸の富裕さはその華やかな家具に明らかでした。
C1 noun /ˈɒfʃuːt/

offshoot

分岐
Meaning
A branch or result that develops from something larger or more important.
Example
The startup was an offshoot of a major tech company.
そのスタートアップは大手テクノロジー企業からの分岐でした。
C1 verb /ˈoʊvərˌhɔːl/

overhaul

完全な改修
Meaning
to examine thoroughly and repair or improve something that is worn or ineffective
Example
The company decided to overhaul its outdated computer system.
会社は古くなったコンピュータシステムのオーバーホールを決定した。
C2 adjective /ˈɑːsɪˌfaɪd/

ossified

骨に変わった、硬直した
Meaning
Turned into bone or become rigid; unwilling to change.
Example
The company had an ossified management structure that resisted innovation.
その会社は、革新に抵抗する硬直した管理構造を持っていました。
A1 adverb /ɔːf/

off

オフ
Meaning
away from a place, position, or time; not functioning
Example
He turned off the light before leaving the room.
彼は部屋を出る前に電気をオフにしました。
C1 noun /əbˈzɜːrvətɔːri/

observatory

天文台
Meaning
A building equipped for observing astronomical or meteorological events.
Example
The observatory is open to the public on weekends.
天文台は週末に一般公開されています。
B2 adverb /əˈfɪʃəli/

officially

公式に
Meaning
in a formal or authorized way
Example
The building was officially opened by the mayor.
その建物は市長によって公式に開かれました。
B2 noun /oʊk/

oak

オークの木
Meaning
a large tree that produces acorns and has strong, hard wood
Example
The old oak tree provided shade for the entire yard.
古いオークの木は庭全体に日陰を提供しました。
C1 verb /ˈɔːstrəˌsaɪz/

ostracize

追放する
Meaning
to exclude someone from a group or society; to banish or shun
Example
After the scandal, he was ostracized by his former colleagues.
スキャンダル後、彼は元同僚に追放された。
B1 noun /əˈpɪn.jən/

Opinion

意見
Meaning
a view or judgment formed about something; a belief or assessment based on grounds short of proof
Example
In my opinion, this is the best solution.
私の意見では、これは最良の解決策です。
B2 verb /ˌoʊvərˈlʊk/

overlook

見落とす
Meaning
to fail to notice or consider something; to have a view from above
Example
It's easy to overlook small details when you're in a hurry.
急いでいると、細かい点を見落とすことがあります。
B1 verb /ˈɒpəreɪt/

operate

操作する
Meaning
to function; to control or manage; to perform surgery
Example
The surgeon will operate on the patient tomorrow.
外科医は明日患者を手術します。
B2 adjective /əˈfen.sɪv/

Offensive

攻撃的な; 侮辱的な; 攻撃的
Meaning
causing displeasure or resentment; insulting; aggressive
Example
His offensive remarks hurt everyone's feelings.
彼の攻撃的な発言は、全員の気持ちを傷つけました。
B2 noun /əˈfɛns/

offense

犯罪
Meaning
an illegal act; a crime
Example
The offense was committed in broad daylight.
その罪は昼間に犯されました。
B2 noun /ˌoʊ.vɚˈkraʊ.dɪŋ/

overcrowding

過密
Meaning
Excessive crowd or packed condition, having more people or vehicles in a place than the approved capacity.
Example
The subway system suffers from severe overcrowding during peak hours.
地下鉄システムはピーク時にひどい過密状態に苦しんでいます。
C1 noun /ˈɔːrθədɑːksi/

orthodoxy

正統
Meaning
traditional or generally accepted beliefs and practices
Example
The religious leader defended the orthodoxy of the faith.
宗教指導者は信仰の正統性を守った。
A1 adjective /oʊˈkeɪ/

ok

わかった
Meaning
used to indicate agreement, approval, or understanding
Example
Okay, let's go to the park.
わかった、じゃあ公園に行こう。
B2 noun /ɒpˈtɪʃən/

optician

眼鏡技師
Meaning
A person who makes or sells glasses and contact lenses.
Example
The optician adjusted my new glasses to fit better.
オプティシャンは私の新しい眼鏡をより良くフィットするように調整しました。
B2 adjective /ˌɔːɡənaɪˈzeɪʃənəl/

organizational

組織的
Meaning
relating to the structure or arrangement of a company or group
Example
He works on improving the organizational structure of the company.
彼は会社の組織構造を改善するために働いています。
A1 pronoun, noun, adjective /wʌn/

one

一
Meaning
the number equivalent to the sum of zero and one; a single person or thing
Example
Only one student answered the question.
ただ一人の学生が質問に答えました。
B2 noun /ˈaʊtskɜːrts/

outskirts

都市の郊外
Meaning
The outer parts of a town or city, away from the center.
Example
They moved to the outskirts of the city for a quieter life.
彼らは静かな生活を求めて都市の郊外に引っ越しました。
A1 adjective /ˈʌðər/

other

他の
Meaning
used to refer to something different from the one already mentioned or known
Example
I don't want this one, I will take the other one.
これを欲しくない、他のを取るつもりだ。
B2 adjective ɔːrˈɡæn.ɪk

organic

有機
Meaning
Produced or involving production without the use of chemical fertilizers, pesticides, or other artificial agents.
Example
Organic farming improves soil health and reduces pollution.
有機農業は土壌の健康を改善し、汚染を減少させます。
B1 noun /ˌɒp.əˈtjuː.nə.ti/

opportunity

チャンス
Meaning
A favorable chance or set of circumstances that makes it possible to do something.
Example
She seized the opportunity to study abroad.
彼女は海外で勉強するチャンスをつかんだ。
C2 noun /ˌɒktədʒəˈnɛəriən/

octogenarian

80歳代の人
Meaning
A person who is between 80 and 89 years old.
Example
The octogenarian still jogs every morning to stay healthy.
そのオクトジェネリアンは毎朝健康を維持するためにジョギングをしています。
C1 verb ˈɔːr.kɪ.streɪt

orchestrate

調整する
Meaning
To plan or coordinate the elements of (a situation) to produce a desired effect, especially surreptitiously.
Example
He skillfully orchestrated the entire event.
彼は巧妙に全体のイベントを調整しました。
B2 noun /əˌrɪʒ.əˈnæl.ə.ti/

Originality

独創性
Meaning
the quality of being novel or unusual; the ability to think independently and creatively
Example
The artist's work showed great originality and creativity.
アーティストの作品は大きな独創性と創造性を示した。
C2 noun /ˈoʊ.vər.let/

Overlet

ベッドパッド
Meaning
a thin mattress or pad placed over a bed for additional comfort
Example
The overlet makes the bed more comfortable to sleep on.
オーバーレットはベッドをより快適にして眠りやすくします。
C1 adjective /əˈblaɪdʒɪŋ/

obliging

親切な
Meaning
Willing to help or do favors; accommodating.
Example
The staff at the hotel were very obliging and friendly.
ホテルのスタッフはとても親切で友好的でした。
B2 noun /əbˈzɜːvər/

observer

観察者
Meaning
a person who watches or notices something
Example
The observer took notes during the meeting.
観察者は会議中にメモを取った。
B2 verb /ˈɒkjʊpaɪ/

occupy

占める / 占有する / 居住する
Meaning
to take up space or time; to live or work in a place
Example
The new family will occupy the house next month.
新しい家族は来月その家に入居する予定です。
C1 adverb /ˈaʊtwədli/

Outwardly

外見上; 表面的に;
Meaning
on the surface; externally; in appearance
Example
Outwardly, he seemed calm, but inside he was nervous.
外見上は落ち着いて見えましたが、内心では緊張していました。
C2 adjective /ˈɒkjʊlər/

ocular

眼科の
Meaning
Relating to the eye or vision.
Example
The patient was referred to a specialist for ocular treatment.
患者は眼科専門医に紹介されました。
A1 preposition, adverb /ˈoʊvər/

over

上に
Meaning
across, on top of, or beyond
Example
The book is lying over the table.
本はテーブルの上にあります。
B1 noun /ˌɑk.jəˈpeɪ.ʃən/

Occupation

職業; 仕事; 占領
Meaning
a job or profession; the action of taking control of a place
Example
Teaching is her chosen occupation.
教えることは彼女の選んだ職業です。
A2 adjective /ˈɑp.ə.zɪt/

Opposite

反対の; 完全に異なる; 向かい合っている; 逆の;
Meaning
Contrary; completely different; facing each other; reverse;
Example
They have opposite views on politics but remain good friends.
彼らは政治に関して対立した見解を持っていますが、良い友達のままです。
B1 verb /əˈkɜːr/

occur

発生する
Meaning
to happen or take place; to be found or present
Example
The accident occurred at the intersection during rush hour.
事故はラッシュアワーの交差点で発生しました。
B2 noun ɔːˈɡæn.ɪk fuːdz

organic foods

オーガニック食品
Meaning
Food produced without the use of chemicals such as artificial pesticides, fertilizers, or other artificial agents.
Example
Organic foods are healthier than processed foods.
オーガニック食品は加工食品よりも健康的です。
A1 preposition /ʌv/

of

の
Meaning
expressing the relationship between a part and a whole
Example
The book is on the table, in front of the window.
本はテーブルの上にあり、窓の前にあります。
B2 noun /ˈɔːkɪstrə/

orchestra

オーケストラ
Meaning
a large group of musicians playing different instruments together
Example
The orchestra performed beautifully at the concert.
オーケストラはコンサートで素晴らしい演奏をしました。
B2 noun /ˈoʊ.vər ɡroʊθ/

Over growth

過剰成長
Meaning
excessive growth beyond normal size; too much development or expansion
Example
The overgrowth of weeds made the garden look untidy.
雑草の過剰な繁茂が庭を乱雑に見せた。
C1 noun /ˈɒn.slɔːt/

onslaught

猛攻
Meaning
A fierce or destructive attack.
Example
The village faced an onslaught of enemy forces.
その村は敵軍の猛攻に直面しました。
C1 noun /oʊθ/

Oath

誓い
Meaning
a solemn promise or declaration; a sworn statement
Example
The doctor took an oath to help patients.
医師は患者を助けることを誓いました。
C2 adjective /ˈoʊ.vɔɪd/

ovoid

卵型
Meaning
egg-shaped; resembling an oval or ellipse
Example
The artist painted an ovoid shape in the center of the canvas.
アーティストはキャンバスの中央に卵型の形を描きました。
A2 verb /ˈɔːfər/

offer

申し出る
Meaning
to present something for acceptance or rejection; to propose
Example
She offered to help with the project.
彼女はプロジェクトを手伝うと申し出た。
C2 adjective /əbˈtruːsɪv/

obtrusive

目障りな
Meaning
noticeable in an unpleasant or unwelcome way; intrusive
Example
The advertisement was so obtrusive that it ruined the user’s experience.
その広告はあまりにも目立ちすぎて、ユーザーの体験を台無しにしました。
C2 noun /ˈɔːrdʒi/

orgy

乱行
Meaning
A wild party involving excessive indulgence, especially of a sexual nature.
Example
The novel described a scandalous orgy in a wealthy mansion.
その小説は、裕福な邸宅でのスキャンダラスな乱行を描いています。
B2 verb /ˌoʊvərˈpeɪ/

overpay

過剰に支払う
Meaning
To pay more than is necessary or reasonable.
Example
She realized she had overpaid for the concert tickets.
彼女はコンサートのチケットに多く支払ったことに気づきました。
C1 adjective /ˌɒmnɪˈprezənt/

omnipresent

至る所に存在する
Meaning
(of God) present everywhere at the same time.
Example
Social media has become an omnipresent force in modern society.
ソーシャルメディアは現代社会において至る所に存在する力となりました。
C2 noun /ˈɒbsɪkwi/

obsequy

葬儀
Meaning
A funeral rite, usually used in plural form obsequies.
Example
The village gathered for the obsequy of their beloved teacher.
村人たちは、愛する教師の葬儀のために集まりました。
C1 adjective /oʊˈbiːs/

obese

肥満
Meaning
Extremely overweight; having an excessive amount of body fat.
Example
The doctor advised the obese patient to adopt a healthier lifestyle.
医者は肥満患者に健康的な生活様式を採用するように勧めました。
B2 noun /ˈaʊtˌbreɪk/

outbreak

発生
Meaning
a sudden start or occurrence of something unpleasant, like disease or violence
Example
There was an outbreak of flu in the city.
街でインフルエンザが発生した。
C1 verb ˈɔː.kɪ.streɪ.tɪd

orchestrated

精巧に組織された
Meaning
Planned or coordinated carefully and deliberately.
Example
The attacks were orchestrated with precision.
攻撃は正確に組織されていた。
C1 adjective əˈblɪv.i.əs

oblivious

無自覚
Meaning
Being completely unaware of surrounding events.
Example
He was oblivious to the noise around him while reading.
彼は読書中に周りの騒音に全く無自覚だった。
B2 adjective + noun ˈɒptɪməl ˈtempərətʃər

optimal temperature

最適温度
Meaning
The best or most favorable temperature for a particular purpose
Example
Winter provides optimal temperature for farming.
冬は農業に最適な温度を提供します。
A1 conjunction /ɔːr/

or

または
Meaning
used to link alternatives
Example
You can have tea or coffee.
お茶かコーヒーをお選びいただけます。
C1 adjective əʊˈpeɪk

opaque

不透明, 理解しにくい
Meaning
Not able to be seen through; not transparent; difficult to understand.
Example
The glass was too opaque to see through.
そのガラスは不透明すぎて、透けて見えませんでした。
C1 noun /əbˈzɜːvəns/

observance

遵守
Meaning
The practice of following a custom, rule, or religious law.
Example
The festival is held in observance of a centuries-old tradition.
その祭りは、数世代にわたる伝統を遵守して行われます。
B1 adjective /əˈkeɪ.ʒən.əl/

Occasional

偶然の
Meaning
occurring infrequently or irregularly; happening from time to time
Example
She enjoys occasional walks in the park.
彼女は公園で偶然の散歩を楽しんでいます。
C1 noun /ˈɒktəɡən/

octagon

八角形
Meaning
A polygon with eight sides and eight angles.
Example
The stop sign is shaped like an octagon.
ストップサインは八角形をしています。
C2 verb /əbˈtruːd/

obtrude

押し付ける
Meaning
to force oneself or one's ideas into a situation uninvited or inappropriately
Example
He didn’t want to obtrude into their private conversation.
彼は彼らのプライベートな会話に押し付けたくなかった。
C2 noun /ˈɔːfəl/

offal

内臓
Meaning
the internal organs and entrails of an animal used as food; waste parts
Example
The butcher prepared sausages using pork offal.
肉屋は豚の臓物を使ってソーセージを作った。
C1 noun /ˈəʊ.nəs/

onus

責任
Meaning
A duty or responsibility, especially a heavy one.
Example
The onus is on the government to provide relief to the victims.
犠牲者に支援を提供する責任は政府にあります。
C1 noun /ˈɔːr.ə.tɔːr.i/

oratory

弁論術
Meaning
The art of public speaking; skilled and confident delivery of speeches to an audience.
Example
His exceptional oratory skills won him the debate competition.
彼の卓越した弁論術は、ディベートコンペティションで彼に勝利をもたらしました。
C1 verb /əˈfɪʃieɪt/

officiate

執り行う
Meaning
To perform official duties, especially in a ceremony or as a referee.
Example
The priest will officiate the wedding ceremony.
司祭が結婚式を司る。
C2 adjective /ˈoʊ.pən ˈhɑrt.ɪd/

Open-hearted

オープンハート; 寛大で誠実; 心温かく受け入れる;
Meaning
Kind and generous; sincere and honest; warmly receptive;
Example
She welcomed the strangers with an open-hearted smile and invited them for dinner.
彼女は見知らぬ人々を心温かい笑顔で迎え、夕食に招待した。
C2 adjective /ˌoʊvərˈwiːnɪŋ/

overweening

過度に傲慢な
Meaning
excessively arrogant or prideful
Example
His overweening pride cost him many friends.
彼の過度の誇りは多くの友人を失わせました。
C1 verb /ˌoʊvərˈrʌn/

overrun

侵略する
Meaning
to spread over or occupy completely; to exceed a limit or time
Example
The garden was overrun with weeds.
庭は雑草に覆われていた。
B2 noun /ˈoʊtˌmiːl/

oatmeal

オートミール
Meaning
A type of porridge made from ground oats, often eaten for breakfast.
Example
She eats a bowl of oatmeal every morning for breakfast.
彼女は毎朝、朝食にオートミールを一杯食べます。
C1 noun /ˈɑd.ɪ.ti/

Oddity

珍奇な現象
Meaning
something that is strange or unusual; a peculiar trait
Example
His habit of sleeping standing up was considered an oddity.
彼の立って寝る習慣は珍奇な現象と見なされていました。
C2 noun ˌɒbfəsˈkeɪʃən

obfuscation

難解化, 混乱
Meaning
The action of making something obscure, unclear, or unintelligible.
Example
The obfuscation of the data made it difficult to interpret.
データの難解化により、解釈が困難になりました。
C2 verb /ˌoʊvərˈstraɪd/

overstride

大きな一歩で越える
Meaning
To stride over something; to step across with long steps.
Example
He managed to overstride the narrow stream with ease.
彼は狭い小川を簡単に越えることができました。
B2 noun oʊˈbiː.sə.t̬i

obesity

肥満
Meaning
The condition of being grossly fat or overweight.
Example
Obesity increases the risk of diabetes and heart disease.
肥満は糖尿病と心臓病のリスクを高めます。
C1 verb /ˌoʊvərˈriːtʃ/

overreach

過剰な努力
Meaning
to go beyond what is proper, acceptable, or achievable; to overextend
Example
The politician overreached by making promises he couldn't keep.
その政治家は約束を守れなかったことで過剰な努力をしました。
A2 adjective /ɒd/

Odd

奇妙な; 異常な; 正常または予想されるものとは異なる
Meaning
strange; unusual; different from what is normal or expected
Example
That's an odd way to solve the problem.
それは問題を解決する奇妙な方法です。
B2 verb /əˈrɪdʒɪneɪt/

originate

起源する
Meaning
to come into existence; to begin; to create or produce
Example
The tradition originated in ancient times.
その伝統は古代の時代に起源を持っています。
C2 noun /ˈɑːbəlɪsk/

obelisk

オベリスク
Meaning
A tall, four-sided, narrow tapering monument with a pyramid-shaped top.
Example
The ancient Egyptians built obelisks to honor their gods.
古代エジプト人は神々を讃えるためにオベリスクを建てました。
C1 verb /aʊtˈlæst/

outlast

他より長く続く
Meaning
to continue longer than; to endure beyond someone or something else
Example
The old castle has outlasted many generations.
その古い城は多くの世代を超えて生き残りました。
B2 noun /ˌɒb.zəˈveɪ.ʃənz/

observations

観察
Meaning
The action or process of observing something carefully.
Example
Observations of distant galaxies provide new insights.
遠くの銀河の観察は新たな洞察を提供します。
C2 adjective /ˈoʊdiəs/

odious

忌まわしい
Meaning
extremely unpleasant or repulsive
Example
The dictator was remembered for his odious crimes.
その独裁者は彼の忌まわしい犯罪で記憶されました。
C2 noun /ˌɔːrdɪˈneɪʃən/

ordination

任命式
Meaning
The ceremony of conferring holy orders or official religious authority.
Example
The church held a special service for the ordination of new priests.
教会は新しい神父の任命のために特別なサービスを行いました。
C2 verb /ˌoʊvərˈliːp/

overleap

飛び越える
Meaning
To jump over something; to omit or disregard something.
Example
He managed to overleap the fence easily.
彼は簡単にフェンスを飛び越えました。
B2 noun ˈɒksɪdʒən prəˈdʌkʃən

oxygen production

酸素生産
Meaning
The process of generating oxygen through photosynthesis or other means.
Example
Plants are vital for oxygen production and the maintenance of life.
植物は酸素の生産と生命の維持に不可欠です。
C2 noun /ˈɒlɪv brɑːntʃ/

olive-branch

オリーブの枝
Meaning
A symbol of peace or reconciliation; an offer to end conflict.
Example
He extended an olive-branch to his rival after years of hostility.
彼は長年の敵対後、ライバルにオリーブの枝を差し出した。
C1 verb /ˈɒs.ɪ.leɪt/

oscillate

二つの点または状態の間で前後に動くまたは揺れる
Meaning
To swing or move back and forth between two points or states
Example
The stock market tends to oscillate during uncertain times.
株式市場は不確実な時期に振動しがちです。
B1 noun /ˈɔr.ə.ʒɪn/

Origin

起源
Meaning
the point or place where something begins, arises, or is derived; the source
Example
Scientists are studying the origin of the universe.
科学者たちは宇宙の起源を研究しています。
C1 adjective /ɔːˈneɪt/

ornate

華やかな
Meaning
elaborately or highly decorated
Example
The palace hall was filled with ornate furniture and paintings.
宮殿のホールは華やかな家具と絵画でいっぱいだった。
C1 adjective /əbˈtjuːs/

Obtuse

鈍い; 理解が遅い; 愚か
Meaning
annoyingly insensitive or slow to understand; lacking in intelligence or perception
Example
He was being deliberately obtuse about the instructions.
彼は指示に関して意図的に鈍かった。
C2 adjective /ˈɒsiəs/

osseous

骨のような
Meaning
consisting of or turned into bone; bony
Example
The fossil showed osseous structures of the ancient creature.
化石は古代の生物の骨のような構造を示しました。
A1 adverb /ˈɔːfən/

often

しばしば
Meaning
frequently, many times
Example
I often visit my grandparents on weekends.
私は週末にしばしば祖父母を訪れます。