It's related to the word "copiosus," meaning "copious," which means plentiful or abundant.
Here are some English words derived from "copia":
* Copious: Abundant in quantity, plentiful
* Copiously: Abundantly, plentifully
* Copy: A reproduction of something, suggesting a plentiful supply
* Copier: A machine that makes copies, suggesting abundance
* Ample: Abundant in size or amount, plentiful