The New Dictionary of Cultural Literacy, Third Edition. 2002.
plural
The grammatical category in nouns, pronouns, and verbs that refers to more than one thing. Most nouns become plural with the addition of -s or -es:hats,chairs,dishes,countries, and so on. Some nouns form the plural in other ways, as in children,feet,geese, and women. (Comparesingular; seeagreement.)