English majors and google searchers extraordinaire?

Question

What is it called when you define a word with itself?

Ex: run (verb): to run

I know you are not supposed to define a word with itself. But isn't there a term for that? I could have sworn that a former English teacher told me there was a word for it.

Thanks for the help!

Answer 1

I would say circular definition.
I'll ask a friend and get back to you if I find anything else.

Answer 2

It's called self-reference. It's also sometimes called a paradox of self-reference because when you rely on a self-reference you often end up in an illogical place or somewhere that you had not expected.