Lemma

Lem″ma (lĕm″mȧ), n.; pl. L. Lemmata (–mȧ‐tȧ), E. Lemmas (–mȧz). [L. lemma, Gr. λη̑μμα anything received, an assumption or premise taken for granted, fr. λαμβάνειν to take, assume. Cf. Syllable.] A preliminary or auxiliary proposition demonstrated or accepted for immediate use in the demonstration of some other proposition, as in mathematics or logic.