Define means: "to give a definition of something"

I got a great treat in the mailbox today: the latest issue of Ability, the Magazine of the Church of Scientology of Illinois.

So it would seem that some former tenant of my apartment was a Scientologist.

I can't say I'm completely surprised--when I first moved in, I could intuitively feel that the place had a lower-than-average concentration of body thetans.

The magazine opens with an article excerpted from an old work of L. Ron himself, about "our biochemical society", in which we see Mr. Hubbard mimic the best analytic philosophy by beginning with the clarification of terms:

Chemical means "of or having to do with chemicals."

Ohhhhh.