pronoun
Basic interrogative or indefinite time word. It asks about a time, or appears in clauses such as いつ来るか and expressions like いつでも.
次の電車はいつ来ますか。
When does the next train come?
いつ終わるか分かりません。
I don't know when it will end.
pronoun
normal times; ordinary days
Dated use meaning ordinary or usual times. It is not the normal modern way to say this; modern Japanese would usually use expressions such as 普段 or 平素.
古い文章では、「いつ」が「普通の日々」を指すことがある。
In old writing, いつ can refer to ordinary days.
Native Japanese time interrogative. The kanji spelling 何時 is conventionally associated with 'what time/when', but the reading いつ is a special reading rather than a regular character-by-character reading.