What does the latin root kilo mean?

The Latin root "kilo" means "thousand". It comes from the Greek word "khilioi", which also means "thousand".

This is why we use "kilo" in words like:

* Kilogram: A unit of mass equal to 1,000 grams.

* Kilometer: A unit of distance equal to 1,000 meters.

* Kilowatt: A unit of power equal to 1,000 watts.