1
general::
Relax, take some time off from what one is doing, as in We've been at it long enough; let's take five. This term is short for "take five minutes off." [Slang; first half of 1900s] For a synonym, see TAKE A BREAK.
American Heritage Idioms
2
general::
Phrase(s): take five
Sl. to take a five-minute rest period; to take a short break. • Okay, everybody. Take five! • Hey, Bob. I’m tired. Can we take five?
McGrawhill's American Idioms And Phrasal Verbs