The Allen and Greenough is still under construction;
so some links may not work quite the way you would expect.
22. The inflection of Nouns, Adjectives, Pronouns,
and Participles to denote gender, number, and case is called Declension,
and these parts of speech are said to be declined.
The inflection of Verbs to denote voice, mood, tense, number, and
person is called Conjugation, and the verb is said to be
NOTE: Adjectives are often said to have inflections of
comparison. These are, however, properly stem-formations made by
derivation (§124, footnote).