Noun
third cousin (plural third cousins)
A grandchild of one's grandparent's first cousin.
I had a buddy of mine call up the other day, all upset 'cause he slept with his third cousin. And I'm like, "Man, if it upsets you that much, quit countin' them!" Larry the Cable Guy
In order to have a couple of shamans on hand in your group, you're willing to put up with the occasional third cousin who's schizophrenic. Robert Sapolsky