The Question:

What is the etymology of the word "trivia"?

The Answer:

"Trivia" is a fairly recent (1920) noun form of the word "trivial" which comes from the Latin trivialis. Trivialis means “that which is in, or belongs to, the crossroads or public streets; hence, that may be found everywhere, common.” It is derived from trivium, a place where three roads meet.

—The Fact Monster