Applied relativity (or, what to call your cousin)

My old friend Don answers the question in my post from yesterday about the naming of cousins:

"Imagine the family as a tree (computer science, not biology), with the common ancestor as the root and only two branches of interest, one leading to each cousin. Assume the two branches have depths X and Y, where X <= Y. The two people are (X-1)th cousins, (Y-X) times removed. For you and Captain Thom X=2 (the distance from you to your grandmother) and Y=3 (he's a generation farther down). You're first (2-1) cousins, once (3-2) removed.

That is good to know, and now that it is on the blog I will always know where to find it.