overnight
overnight はTOEIC 730レベルの英単語で、「一泊して、一晩中、一泊の、一夜にして」という意味があります。発音記号は /ˈoʊvɚnaɪt/ です。
一泊して
解説 Definition
宿やホテル、友人の家などに一晩だけ滞在して翌日まで過ごすことを表す副詞です。stayやstopとよく結びつき、旅先や出張先でその場に泊まることを示します。単に「一晩中」続くという意味ではなく、「一泊して」という行動に焦点があります。
As an adverb, "overnight" often means staying somewhere for one night and leaving the next day. It is commonly used with verbs like stay or stop when talking about a hotel, a friend's house, or another place during a trip. In this sense, it focuses on the action of spending the night there, not simply on something continuing all night.
覚え方のコツ Memory Tip
over + night で「夜をまたぐ」と捉えると定着しやすい。night だけでは“夜に”だが、over が付くと“夜を越えて翌朝まで”の感覚になる。work overnight, stay overnight, ship overnight が頻出。比喩では become successful overnight のように「一夜にして急に」。all night は行為が夜じゅう続くこと、overnight は夜をまたいだ結果や変化まで含みやすい、と分けると混同しにくい。
Think of "overnight" as "over + night," or going across the night into the next morning. "Night" alone just means the time of night, but "overnight" suggests crossing that time boundary. This helps with common phrases like stay overnight, work overnight, and ship overnight. It is also different from "all night," which usually focuses only on something continuing during the whole night.
例文
We stayed overnight at a small hotel near the station.
私たちは駅の近くの小さなホテルに一泊して泊まった。
Because the roads were closed, the team had to stop overnight in the town.
道路が閉鎖されていたので、チームはその町に一泊して足止めされた。
If you visit us this weekend, you can stay overnight in the guest room.
今週末に来るなら、客間に一泊して泊まれるよ。
一晩中
(意味 2)解説 Definition
動詞を修飾し、作業・移動・保管・発酵などが夜の時間を通して翌朝まで続くことを表す。work overnight, drive overnight, leave it overnight のように、継続した結果が朝に現れる場面で使われる。
Overnight means during the whole night or by the next morning. It is used for travel, staying somewhere, delivery, or changes that happen very quickly. In some contexts, it suggests that something happened faster than expected.
覚え方のコツ Memory Tip
overnight を副詞で見ると、「夜を越えるようにそのまま続ける」という時間の流れが中心になる。engineers worked overnight なら夜間ずっと作業し、dough rises overnight なら寝ている間に変化が進む。形容詞の overnight trip が名詞の性質を決めるのに対し、副詞は動詞の進み方や放置時間を説明する。all night より、翌朝まで置く・続ける結果に意識が向きやすい。
Break it into `over` + `night`: something goes across the night until morning. That makes it easy to connect with phrases like `stay overnight` or `work overnight`. It can also mean a very sudden change, as in `become famous overnight`.
例文
The engineers worked overnight to fix the system before morning.
エンジニアたちは朝までにシステムを修復するために夜通し働いた。
The dough needs to rise overnight in the refrigerator.
生地は冷蔵庫で夜通し発酵させる必要がある。
She drove overnight to reach the city before sunrise.
彼女は日の出前に街に着くために夜通し運転した。
一泊の
(意味 3)解説 Definition
名詞の前で使い、宿泊・移動・用具が「一晩泊まる／一晩分で足りる」性質をもつことを示す。overnight stay は滞在そのもの、overnight bag は一泊に必要な荷物向けで、旅行・出張の予定を簡潔に表せる。
As an adjective, overnight is used before a noun to show that something involves one night away from home or is meant for one night's use. It is common with words like stay, trip, bag, or train. The word helps describe short travel or lodging plans in a simple and practical way.
覚え方のコツ Memory Tip
certain は「確信している、確かな」、un- は not の働きをする否定の接頭辞です。uncertain は人が判断や答えに自信を持てず、「そうだ」と言い切れない状態として覚えましょう。I’m uncertain about the result のように be uncertain about ... の形で、結果・理由・選択・相手の意図などについて迷う時に使います。sure より少し書き言葉寄りで丁寧です。
Think of overnight as over + night, meaning something that goes across one night. An overnight stay lasts for one night, and an overnight bag is for the things you need for that one night. This image makes the word easy to remember for short travel or business trips.
例文
We booked an overnight stay near the station.
駅の近くで一泊の滞在を予約しました。
She packed an overnight bag for the business trip.
彼女は出張のために一泊用のバッグを用意しました。
They planned an overnight trip to Kyoto after the conference.
会議のあと、彼らは京都への一泊の旅行を計画しました。
一夜にして
(意味 4)解説 Definition
短い時間、特に一晩のうちに状況が大きく変わることを表す副詞です。changeやbecomeなどとよく使われ、「一夜にして」「突然」の感覚を出します。文字通り一晩を指すより、急激で目立つ変化を強調することが多いです。
Overnight is an adverb that describes a big change happening in a very short time, often within one night. It is commonly used with verbs like change, become, or grow to show that something happened suddenly and was very noticeable. It can also mean that something continues through the night or is completed by the next morning.
例文
The company became famous overnight after its video went viral.
その会社は動画が話題になり、一夜にして有名になった。
Overnight, public opinion changed as new information spread online.
新しい情報が広まり、世論は一夜にして変わった。
Temperatures dropped overnight, and the streets were covered with ice by morning.
気温が一晩のうちに下がり、朝には通りが氷でおおわれていた。
overnight の語源・成り立ち Etymology
古英語 ofer（～を越えて）+ niht（夜）から成る複合語。「夜を越えて・夜通し」が原義で、一晩かけて何かが起こる様子を表す。関連語: night（夜）、overdo（やりすぎる）。夜という時間を丸ごと飛び越えるイメージが「一晩中・翌朝までに」の意味を生んだ。
"Overnight" comes from Old English elements meaning "over" and "night." Its original idea was to go across the night or last through the night, and this later developed into meanings like staying for one night or happening by the next morning.
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