Grammatical category for the variation in form of nouns, pronouns, and any words agreeing with them, depending on how many persons or things are referred to. (www.wordreference.com/English/definition.asp?en=number 12; http://www.isocat.org/datcat/DC-1298) A grammatical number is a morphological category characterized by the expression of quantity through inflection or agreement. (http://en.wikipedia.org/wiki/Grammatical_number 17.11.06)