lemma
UK[ˈlemə]US[ˈlemə]
n
A heading indicating the subject or argument of a literary composition, a gloss, or an annotation.
n
A word or phrase used as the headword in a dictionary, glossary, or index, under which related words, inflections, or meanings are listed.
n
(Mathematics, Logic) A subsidiary or intermediate theorem in an argument or proof.
Etymology
The word 'lemma' entered English in the late 16th century via Latin, directly from the Greek word 'λῆμμα' (lēmma), meaning 'something received' or 'a premise'. This Greek term itself derives from the root of the verb 'λαμβάνειν' (lambanein), 'to take'. The semantic journey from the concrete act of 'taking' to the abstract concept of a 'thing taken' or 'assumption' is clear. In its scholarly adoption, 'lemma' evolved from meaning a basic premise or assumption in an argument to its specialized modern senses: the headword taken as the basis for dictionary entries and the subsidiary theorem taken as a given within a mathematical proof.
Analysis
The entire word 'lemma' is a simplex borrowing from Greek. It functions as a single, unanalyzable unit in modern English.
Examples
In linguistics, the dictionary entry for 'running' is listed under its base form, the lemma 'run'.
The philosopher began his complex argument by stating a fundamental lemma upon which his entire thesis depended.
Before solving the main problem, the mathematician had to prove a small but crucial lemma.