This is the 3772nd most frequent Arabic word.
الزمن
"الزمن" in English means "time."
Here, الزمن refers to time in the general sense of its ongoing passage.
الزمن يمضي بسرعة.
Time passes quickly.
In this sentence, الزمن refers to a specific amount or instance of available time.
علينا الاستفادة من الزمن المتاح.
We need to make use of the available time.
Here, الزمن is used to describe a specific period in the past.