The declination (Latin declinare, " bend ") in the grammar of a language formally describes the rules by which certain types of words (especially nouns, pronouns and adjectives ) in accordance with the grammatical categories case ( case ), number (number) and genus (gender ) change their shape. Not every language uses all of these categories. The words are declined. The declination is in addition to the conjugation of the verb is a form of flexion, the variability of words or word types.
A language can bend all the words in a pattern and then has a declination (or Deklinationsschema ), or they can bend different words for different schemes and then has several declensions. In languages that have diffraction, the inflected languages , the role of a noun in a sentence is determined by the Deklinationsform.
Words which can not be declined are called indeklinabel. Some agglutinative languages have no declination, such as Japanese or Hungarian.