1.Linguisticsa. In certain languages, the inflection of nouns, pronouns, and adjectives in categories such as case, number, and gender. b. A class of words of one language with the same or a similar system of inflections, such as the first declension in Latin. 2. A descending slope; a descent. 3. A decline or decrease; deterioration: States and empires have their periods of declension (Laurence Sterne). 4. A deviation, as from a standard or practice.
ETYMOLOGY:
Middle English declenson, from Old French declinaison, from Latin dclnti, dclntin-, grammatical declension, declination. See declination.