de ‧ clen ‧ sion /dɪˈklenʃ ə n/ BrE AmE noun [countable]
[ Date: 1400-1500 ; Language: French ; Origin: déclinaison , from Latin declinare 'to turn aside, inflect' ]
1 . the set of various forms that a noun, ↑ pronoun , or adjective can have according to whether it is the ↑ subject , ↑ object etc of a sentence in a language such as Latin or German
2 . a particular set of nouns etc that all have the same set of forms