In grammar, a part of speech is the role that a word (or sometimes a phrase) plays in a sentence.
Words are not inherently one part of speech or another, many verbs and nouns are spelled identically, for instance, denoting the action and the name of the action, respectively:
- neigh
- break
- outlaw
Not all adverbs end in -ly and not all words ending in -ly are adverbs.
- tomorrow, slow, fast, crosswise can all be adverbs.
- leisurely, friendly, ugly are all adjectives.
Even words with primarily grammatical functions can be used as verbs or nouns, as:
- We must look to the hows and not just the whys.
- Miranda was to-ing and fro-ing and not paying attention.
Common ways of delimiting words by function include:
In transformational-generative grammar parts of speech are known as Lexical categories.