Vocabulary elements categorised by word class or part of speech (verb, noun, adjective etc), as well as by word form (contraction, prefix, suffix etc).
These pages deal mainly with vocabulary, for example word lists, meanings and sample sentences with words in use. But see also the grammar of parts of speech.
Traditionally, there are four major word classes (verb, noun, adjective, adverb) and four other word classes (preposition, pronoun, conjunction, interjection), making eight word classes (or parts of speech) in total. But note that some grammarians use different systems and may have nine or ten different word classes.