Inflection, in grammar, changes in form that words undergo with each change in grammatical function. For example, the English verb write becomes writes in the third person singular of the present tense. Write has 3 additional forms: wrote, written, and writing. This set of inflections for a verb is called conjugation. The set of inflections for a noun or pronoun is called declension. For example, the English noun dog has 4 forms: dog, dogs, dog's, and dogs'.
See also: Grammar.