lemma

definition: the heading that indicates the subject of an annotation or a literary composition or a dictionary entry
example:
speech part: noun
synonyms:
definition: a subsidiary proposition that is assumed to be true in order to prove another proposition
example:
speech part: noun
synonyms:
definition: the lower and stouter of the two glumes immediately enclosing the floret in most Gramineae
example:
speech part: noun
synonyms: flowering glume

How lemma is being used?