Why does the word trivial have form root tri meaning three in it?

You're right to notice the connection between "trivial" and "three"! It's a fascinating linguistic journey.

The word "trivial" comes from the Latin word "trivialis," which literally means "belonging to the crossroads." Here's how it breaks down:

* "Tri-" (from *tres*, meaning "three") referred to the three roads that typically intersected at a crossroads.

* "-vialis" means "of the road," "related to the road," or "belonging to the road."

So, originally, "trivialis" referred to things that were common and found at these crossroads. These places were bustling with activity, where people from different walks of life would gather and share news, gossip, and information.

Over time, the meaning of "trivialis" shifted. It started to be used for things that were ordinary, commonplace, and insignificant, since they were so familiar and common at these crossroads.

The word then transitioned to "trivial" in English, retaining that sense of something being unimportant, insignificant, or lacking in value.

So, although the word "trivial" doesn't directly refer to the number "three" anymore, its origin in the Latin "trivialis" reveals its interesting connection to the concept of crossroads and the everyday things that were found there.