Meaning

noun a subsidiary proposition that is assumed to be true in order to prove another proposition

noun the lower and stouter of the two glumes immediately enclosing the floret in most Gramineae

noun the heading that indicates the subject of an annotation or a literary composition or a dictionary entry

originBorrowed from Ancient Greek λῆμμα (lêmma, “premise, assumption”), from the same root as λαμβάνω (lambánō, “to take”).

Etymology from Wiktionary, CC BY-SA 3.0