Webster defines cousin as "the son or daughter of an aunt or uncle, one related by descent in a diverging line from a known common ancestor". Consider these rules of thumb:

FIRST COUSINS share grandparents in common. SECOND COUSINS share great-grandparents in common. THIRD COUSINS share great-great- grandparents in common, and so on down the line.

In other words, the first, second or third, etc. cousin designation tells you how many grandparents you have to go back to in order to find the ones you share. Tip: Start counting with your grandparents as "one".

The next level in the "removed" designation. If your cousin is not the same number of generations away from your common ancestor, then you are removed. Once removed, twice removed, etc.