Time as a concept — the flow or continuum in which events occur.
時間は金なり。
Time is money.
時間が足りなくて宿題が終わらなかった。
I didn't have enough time to finish my homework.
人生には限られた時間しかない。
We only have a limited amount of time in life.
An hour or hours — a unit or measure of duration (e.g., 'one hour').
映画は2時間だった。
The movie was two hours long.
1時間後に会いましょう。
Let's meet in one hour.
昨日は8時間よく眠った。
I slept well for eight hours yesterday.
A time slot or period — a scheduled period such as a class period or lesson time.
授業の時間は何時からですか？
What time does the class start?
昼休みの時間には図書館が混む。
The library gets crowded during lunchtime.
研修は3時間の予定です。
The training is scheduled to last three hours.