One word can radiate related senses. Polysemy is the capacity of a single lexical item to have multiple meanings that share a historical or conceptual connection, as with head for a body part and for the leader of an organization.

Unlike homonymy, polysemous senses are felt to belong to one word. Dictionaries list them as numbered senses under a single entry. Context selects the intended sense so efficiently that speakers rarely notice the multiplicity.

Semantic change often proceeds by extending existing words rather than inventing new roots, producing polysemy over time. Cognitive linguistics studies the metaphorical and metonymic links among senses. Language technology must disambiguate polysemous items for accurate interpretation.

• Multiple related meanings of one word
• Distinct from accidental homonymy
• Represented as senses under one dictionary entry
• Product of semantic extension over time