declension

noun4

1. •
   The act of declining a word; the act of listing the inflections of a noun, pronoun or adjective in order.
2. •
   A way of categorizing nouns, pronouns, or adjectives according to the inflections they receive.

   • In Latin, 'amicus' belongs to the second declension. Most second-declension nouns end in '-i' in the genitive singular and '-um' in the accusative singular.
3. •
   The product of that act; a list of declined forms.
4. •
   A falling off, decay or descent.