»H is for hapax legomenon.

When I was seven or eight, I read an odd book: I cannot recall the title, but remember that the cover illustration had a gaudy painting of a dark room with a brain in a jar, and a boy standing in studied amazement. The story told of the young boy and his relationship with the brain, which could answer anything; one of the curious bits of trivia it knew as that Jane Austen's posthumously-published Northanger Abbey makes the first printed reference to rounders as "base ball".

What is the technical term for the first occurrence of a word or phrase?

Karen Joy Fowler has written a book in the first-person plural, titled The Jane Austen Book Club.