Grammar, Syntax, Diction, and Useage
from Revising Prose by Richard Lanham
'In traditional English grammar, there are eight parts of speech: verbs, nouns, pronouns, adjectives, adverbs, prepositions, conjunctions, interjections. Grammar, in its most general sense, refers to all the rules that govern how meaningful statements can be made in any language. Syntax refers to sentence structure, to word order. Diction means simply word choice. Usage means linguistic custom.'