n.1 Gram. a the variation of the form of a noun, pronoun, or adjective, by which its grammatical case, number, and gender are identified. b the class in which a noun etc. is put according to the exact form of this variation.
2 deterioration, declining.
Derivatives:
declensional adj.
Etymology: OF declinaison f. decliner DECLINE after L declinatio: assim. to ASCENSION etc.