As a Noun: 1. A single unit of language that is uttered in speech. English = word. 2. A single unit of language that can be represented in writing or speech. In English, it has a space on either side of it when it is written. It can have one or more meanings. English = word. 3. The single smallest unit of language (spoken, written or signed) that carries meaning all by itself. English = morpheme. As a Verb or Adjective: 1. To utter a single unit of language in speech; to say a word. 2. To communicate in language using words, rather than signs.