What does the latin root word quantis mean?

The Latin root word "quantus" means "how much" or "how great". It's related to the concept of quantity, and it's the root of many English words, including:

* Quantify: To express something as a number or amount.

* Quantity: An amount or number.

* Quantum: A discrete unit of energy or matter.

So, "quantus" is about describing the size or amount of something.