Number indicates whether a noun is singular (one) or plural (more than one).
Singular nouns refer to one person, place, thing, or idea.
Plural nouns refer to more than one person, place, thing, or idea.
Rules for forming plurals:
- Most nouns: add -s (cat → cats, dog → dogs)
- Nouns ending in -s, -x, -z, -ch, -sh: add -es (bus → buses, box → boxes)
- Nouns ending in consonant + y: change y to i and add -es (baby → babies)
- Nouns ending in vowel + y: add -s (boy → boys, day → days)
- Nouns ending in -f or -fe: change to -ves (leaf → leaves, knife → knives)
- Irregular plurals: man → men, woman → women, child → children, foot → feet