What Is a Word? Linguistic Definition, Types, and Evolution of Meaning

A word is the smallest free form in language — a unit that can stand alone as an utterance, composed of one or more morphemes, bearing meaning and syntactic function.

Word Classes (Parts of Speech)

• Nouns: Entities (concrete/abstract) — Paris, love, committee.
• Verbs: Actions, states, occurrences — run, be, become.
• Adjectives: Modify nouns — red, beautiful, infinite.
• Adverbs: Modify verbs, adjectives, clauses — quickly, very, however.
• Prepositions: Relate nouns — in, on, under, despite.
• Conjunctions: Connect clauses — and, but, because.
• Interjections: Emotive utterances — wow, ouch, hey.

Semantic Change

Meanings shift over time: semantic broadening (dog = specific breed → all canines), narrowing (meat = all food → flesh), amelioration (knight = servant → noble), pejoration (silly = blessed → foolish). Gay: "carefree" (1300s) → "homosexual" (1900s).

Lexicology

The study of words: etymology, morphology, semantics, lexicography (dictionary-making).