Rule 1 : Add s to the singular noun. Ball -- Balls Egg -- Eggs Rule 2 : Noun ending with o, s, ss, sh, ch or x Add es Bench - Benches Box - Boxes Boss - Bosses Mango - Mangoes Rule 3 : Noun ending with f or fe, change the f or fe to ves thief - thieves life - lives But following are exceptions chief - chiefs roof - roofs hoof - hoofs proof - proofs handkerchief - handkerchiefs Rule 4 : Noun ending in consonant + y Change y to ies City - cities Baby - babies Rule 5 : Noun ending in Vowel + y - Add s Boy - boys monkey - monkeys Exceptions to all of the above rules Child - Children Foot - Feet Goose - Geese Man - Men Mouse - Mice Ox - Oxen Tooth - Teeth Woman - Women Deer, Sheep, Fish, Fruit have same form in singular and plural. Fishes or Fruits is used not for many of different kind but not for many of the same kind. Fruits are good for health means fruits of different kind and not one kind of fruit. Similar We saw variety of fishes in aquiriam means different kind of fishes. Scissors, trousers, spectacles, shorts are always used in plural form.