Lem·ma n.; pl. L. Lemmata E. Lemmas
  1. Math., Logic A preliminary or auxiliary proposition demonstrated or accepted for immediate use in the demonstration of some other proposition, as in mathematics or logic.
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  lemma
       n 1: a subsidiary proposition that is assumed to be true in order
            to prove another proposition
       2: the lower and stouter of the two glumes immediately
          enclosing the floret in most Gramineae [syn: flowering
          glume]
       3: the head of an annotation or gloss
       [also: lemmata (pl)]