Plural: -s, -ões/-ães/-ãos, -is
Plural: -s, -ões/-ães/-ãos, -is means “Most plurals just add -s, but words in -ão and -l change shape”. Words ending in a vowel simply take -s: casa → casas, livro → livros. Formation: vogal + -s · -ão → -ões / -ães / -ãos · -l → -is · -r/-z → -es
Most plurals just add -s, but words in -ão and -l change shape
A1Formation
vogal + -s · -ão → -ões / -ães / -ãos · -l → -is · -r/-z → -es
Explanation
Words ending in a vowel simply take -s: casa → casas, livro → livros. Words ending in -r or -z add -es: mulher → mulheres, luz → luzes. Two groups need memorising. First, -l becomes -is: animal → animais, papel → papéis, difícil → difíceis, azul → azuis (note the accent that appears on papéis). Second, and harder, -ão splits three ways with no rule to predict it: pão → pães, mão → mãos, coração → corações. The -ões group is by far the largest, so it is the safest default, but the other two must be learnt word by word.
Examples
Note
Careful with pronunciation too: some plurals open the stressed vowel — ovo [ˈovu] → ovos [ˈɔvus], osso → ossos, porco → porcos.
FAQ
Plural: -s, -ões/-ães/-ãos, -is — what does it mean and how is it used?
Most plurals just add -s, but words in -ão and -l change shape. Words ending in a vowel simply take -s: casa → casas, livro → livros. Words ending in -r or -z add -es: mulher → mulheres, luz → luzes. Two groups need memorising. First, -l becomes -is: animal → animais, papel → papéis, difícil → difíceis, azul → azuis (note the accent that appears on papéis). Second, and harder, -ão splits three ways with no rule to predict it: pão → pães, mão → mãos, coração → corações. The -ões group is by far the largest, so it is the safest default, but the other two must be learnt word by word.
Plural: -s, -ões/-ães/-ãos, -is — how do you form it?
vogal + -s · -ão → -ões / -ães / -ãos · -l → -is · -r/-z → -es
Plural: -s, -ões/-ães/-ãos, -is — any usage notes?
Careful with pronunciation too: some plurals open the stressed vowel — ovo [ˈovu] → ovos [ˈɔvus], osso → ossos, porco → porcos.