lemma

Từ điển American Heritage Dictionary 4th

I. lem·ma¹ (lĕmʹə)n. pl. lem·mas or lem·ma·ta (lĕmʹə-tə)
1. A subsidiary proposition assumed to be valid and used to demonstrate a principal proposition.
2. A theme, argument, or subject indicated in a title.
3. A word or phrase treated in a glossary or similar listing. [Latin lēmma, from Greek, from lambanein, to take.] II. lem·ma² (lĕmʹə)n.
The outer or lower of the two bracts that enclose the flower in a grass spikelet. [Greek, husk, from lepein, to peel.]