1. Most nouns are made plural by adding s. cat - cats dog - dogs
2. Nouns ending in sh, ch, s, or x are made plural by adding es. bush - bushes class - classes church - churches box - boxes (Exception is animal names, which may be the same in the singular and the plural: fish, fox.)
3. Nouns ending in y preceded by a vowel (a, e, i, o, u, and sometimes y and w) are made plural by adding s. monkey - monkeys key - keys
4. Nouns ending in y preceded by a consonant (any letter not a vowel) are made plural by changing the y to i and adding es. baby - babies lady - ladies
5. Many nouns ending in f or fe are made plural by changing f or fe to ves. knife - knives scarf - scarves wife - wives
6. Nouns ending in o preceded by a vowel are made plural by adding s. rodeo - rodeos radio - radios
7. Some nouns ending in o preceded by a consonant become plural by adding es. potato - potatoes tomato - tomatoes
8. Many two-word and three-word compound nouns are made plural by adding s to the more important noun. daughter-in-law - daughters-in-law passer-by - passers-by
9. Certain nouns change the vowel or add en. man - men foot - feet ox - oxen goose - geese
10. A few nouns are the same in both singular and plural. deer - deer sheep - sheep
11. Some nouns have no singular form. pants - pants scissors - scissors
12. Letters used as letters (as in "the letter b), figures used as figures, signs, or words
used as words (as in the word orange) are made plural by adding an apostrophe plus s.
m - two m's in this word
or - three or's in this sentence
i; t - Dot your i's and cross your t's