Dictionary.com Word FAQs
What are some rules for forming plurals?
The most basic way to form a plural is to add s to the word: apples, cats, mothers. If the word ends in ch, s, sh, ss, x, z, or zz, then you add an es: bunches, thesauruses, dishes, sixes, chintzes. Proper nouns of this type always add -es: Magoulas, Magoulases. Most of the words that end with f, ff, or fe are made plural by changing the ending to -ves, (such as loaves and wives) but there are exceptions that must be memorized or looked up, e.g., beliefs, gulfs, roofs. A few nouns ending in f or ff, including beef, dwarf, hoof, scarf, wharf, and staff have two plural forms: beefs or beeves; dwarfs or dwarves. A word that ends with a combination of a vowel plus y will have an s added: bays, birthdays, cowboys, keys. A word that ends with a combination of a consonant plus y will change the y to ies: babies, faculties, French fries. Proper nouns ending in y form their plurals regularly, and do not change the y to i as common nouns do, e.g., the two Sandys. Words that end in o usually just get s added, but there are exceptions that must be memorized or looked up, such as: echoes, potatoes, volcanoes. Some nouns ending in o preceded by a consonant have two plural forms: buffaloes or buffalos; cargoes or cargos; mosquitoes or mosquitos; zeros or zeroes. Most nouns ending in i form their plurals by adding -s: alibis, khakis, skis, but there are exceptions (chiles). A few nouns undergo a vowel change in the stem: foot, feet; goose, geese; louse, lice; man, men; mouse, mice; tooth, teeth; woman, women. Compounds written as a single word form their plurals the same way that the final element of the compound does. Compounds ending in -ful normally form their plurals by adding s at the end. Compound words, written with or without a hyphen, that consist of a noun followed by an adjective or other qualifying expression form their plurals by making the same change in the noun that is made when the noun stands alone. Some nouns, mainly names of birds, fishes, and mammals, have the same form in the plural as in the singular. Many words indicating nationality or place of origin have the same form in the plural as in the singular. A few names of tribes or peoples have the same form in the plural as in the singular. Many nouns derived from a foreign language retain their foreign plurals. The plural of a word being used as a word is indicated by 's.