Directly from "aequus":
* Equable: Calm, even-tempered, balanced
* Equanimity: Mental calmness, composure
* Equidistant: At the same distance from something
* Equilibrium: A state of balance
* Equivocal: Open to more than one interpretation, ambiguous
* Equine: Relating to horses
With a slight variation in spelling:
* Equal: The same in quantity, size, degree, or value
* Equality: The state of being equal
* Equation: A mathematical statement that shows two expressions are equal
* Equate: To consider something to be the same as something else
Less common, but still related:
* Equilateral: Having all sides equal (e.g., an equilateral triangle)
* Equipartition: The division of something into equal parts
* Equivocation: The use of ambiguous language to mislead
These are just a few examples, and there are many other words that use "equ" as a root.