Theorem: A mathematical statement that is proved using rigorous mathematical reasoning. In a mathematical paper, the term theorem is often reserved for the most important results. Lemma: A minor result whose sole purpose is to help in proving a theorem. It is a stepping stone on the path to prove a theorem. The distinction is rather arbitrary since one mathematician's major is another's minor claim. Very occasionally lemmas can take on a life of their own (Zorn's lemma, Urysohn's lemma, Burnside's lemma, Sperner's lemma).

Friedrich Zorn has written:

'Wormser Chronik' -- subject(s): History

This usually means the upcoming lemma is an adaption of a previous lemma to a mathematical object related to the one in the first lemma.

The plural of "lemma" is "lemmas" or "lemmata".

Raymond O. Zorn has written:

'Church and kingdom' -- subject(s): Church, Kingdom of God