"Lemma"?!

From m-w.com:

Pronunciation: ‘le-m&
Function: noun
Inflected Form(s): plural lemmas or lem ma ta /-m&-t&/
Etymology: Latin, from Greek lEmma thing taken, assumption, from lambanein to take
1 : an auxiliary proposition used in the demonstration of another proposition
2 : the argument or theme of a composition prefixed as a title or introduction; also : the heading or theme of a comment or note on a text
3 : a glossed word or phrase

And here I was thinking my normally straight-laced Differential Equations professor was just trying to be cute or funny or sociable by calling the little theorems we were studying “lemmas”. Or that maybe he meant that they were the solutions to little theoretical problems, or dilemmas, faced by mathematicians…

Shows what I know. At least pondering the possible meanings of the word kept me a little more awake in class (more a reflection of my current hours than of the professor).