Lēm'mā, n.

n.; Lat. pl. LĒM'MA-TĀ; Eng. pl. LĒM-MĀS. [Lat. lemma, Gr. λῆμμα, any thing received, an assumption or premise taken for granted, from λαμβάνειν, to take, assume.] (Math.) An auxiliary proposition demonstrated for immediate use in the demonstration of some other proposition.

Whatever is—so much I conceive to have been a fundamental lemma for Hazlitt—is wrong. De Quincey.