However, you might be thinking of the Latin root "equi", which means:
* Equal
* Same
* Like
This root appears in many words:
* Equilateral: Having equal sides
* Equidistant: At equal distances
* Equanimity: Mental calmness, composure
* Equine: Relating to horses
* Equation: A mathematical statement of equality
So while "Equa" isn't a standalone prefix, "Equi" is a very common one, indicating equality or sameness.