Confusion abounds over the difference between a “second cousin” and a cousin “twice-removed.” If you don’t believe me, just ask the next cousin you come across. I’m here to resolve that problem for all time.
Since about the thirteenth century, second has been used to indicate “next in line,” and around about 1660, it was applied to cousins, to indicate the relationship between the offspring of first cousins. Your first cousin, of course, is the offspring of your parent’s brother or sister. In other words, your mother’s sister’s daughter Griselda is your first cousin. Griselda’s son, the mischievous Herkimer, and your daughter, the adorable little Marzipan, are second cousins.
You and Herkimer are first cousins once-removed. The adjective removed has been used since 1548 to mean “a generation younger or older.” So when Herkimer and his future wife, the shrewish Anaconda, give birth to little Pococurante, that child (of indeterminate gender) will be your first cousin twice-removed.
While we’re at it, the word cousin also has an interesting history. It’s from the Latin consobrinus, which means “mother’s sister’s daughter” (such as Griselda is to you)—but it later had the meaning of either parent’s sibling’s child of either gender. Some languages still retain different words for each of the eight possible “cousin” relationships—mother’s brother’s son, father’s sister’s daughter, etc., etc., etc.
In a broader sense cousin is often used to mean any relation beyond one’s immediate family. Since the early fifteenth century, cousin was a Cornish term of address for anyone related to you either by blood or friendship.
The Bard of Buffalo Bayou has few cousins, and they tend to avoid each other whenever possible, for reasons that are clear in this verse:
My cousin is an awful boor--
He’s churlish and uncouth.
His presence no one can endure,
And that’s the gospel truth.
His conduct must be disapproved,
This rude and loutish cad,
Until he’s gone—then, once removed,
This cousin’s not so bad.