Is quad a word in the English language?

Yes, "quad" is a word in the English language. It has a few different meanings:

* Short for quadrangle: A four-sided figure, especially a square or rectangle.

* Short for quadruplet: One of four children born at the same time.

* Informal abbreviation for quadruped: A four-legged animal.

* A unit of measurement equal to 4: Used in some contexts, especially related to computers.

So, "quad" is a legitimate word depending on the context.