Mom, does 'micro' mean small?

Did you know that people used to think that a disaster ("dis-ast" => ill-starred) happened because the stars were out of line? 

When one of my children was six, he asked me, "Mom, does 'micro' mean small?" My heart started to beat fast. As casually as possible I said, "Why do you ask?"  "Well, I use a microscope to look at small things, a microbe is a small animal and a micron is a small measure. Does micro mean small?" So I explained Greek and Latin roots to him, and without missing a beat, he spouted, "Well in that case, 'tri' means three because a tricycle has three wheels and a triangle has three angles."

We were on our way to a birthday party and at that point we reached our destination so we said goodbye. Three hours later when I went to pick him up, less than 10 meters out the door, my son burst out with, "Mom, I know visible means you can see it, and invisible means you can't see it, so 'in' must mean 'can't'; since invincible means you can't be hurt (think 'superheroes') and 'in' means can't, vincible must mean you can be hurt, right?"

He spent the next six months taking words apart and putting them back together again and checking with me on the meaning. 

If a six-year-old can do it, so can you.​

Here's a start.​

Minute Greek and Latin roots