I appreciate your help, Cacia-san ! And I made a mistake....You're right, "the eleventh hour" is the idiom I'd like to know meaning. Your excellent detailed explanation is so helpful for me. I could understand the correct meaning of "the eleventh hour", thanks to you. BTW this idiom was on my colleague's business mail. My company has suddenly changed content of contract, and our client used such as the idiom... Caciaさんありがとうございます！ そして僕が間違っていました…あなたの言う通り、意味を知りたかったイディオムは"the eleventh hour"です。 あなたの丁寧な説明は本当に助けになりました。 あなたのおかげでイディオムの正しい意味を知ることが出来ました。 ところで、イディオムは僕の同僚のビジネスメールに載っていたものです。 僕の会社が急に契約の内容を変更したら、クライアントがそのようなイディオムを使っていました…。

"Seventh hour" is not an idiom in English — it doesn't have a special meaning. It can mean "the seventh hour after midnight" (7:00 am) or "the seventh hour after dawn" (in the Bible, "the seventh hour" refers to midday, approximately noon to 1:00 pm). Where did you find the phrase? If you can give more context, we might be able to give you a better answer. However, there is an idiom that sounds similar: "the eleventh hour." That phrase means "at the very last moment." It usually implies drama. If a hero arrives at the eleventh hour, he has come right before the catastrophe. If a student waits until the eleventh hour to write his paper, he is very late and might not finish in time.