Ho un libro, una penna e uno zaino.I have a book, a pen and a backpack.

The Italian indefinite article means "a / an" (or "one"): it introduces one thing that is not specific or already known. It has four forms, and you choose by the noun's gender and by the first sound of the word that follows.

Quick shortcut: un (masculine, most words), uno (masculine, before s + consonant, z, gn, ps, pn, x, y), una (feminine, before a consonant), un' (feminine, before a vowel).

The four forms

Form Used before Examples
un masculine nouns starting with a vowel or most consonants un libro (a book), un amico (a friend), un uomo (a man)
uno masculine nouns starting with s + consonant, z, gn, ps, pn, x, y uno studente, uno zaino (a backpack), uno gnocco, uno psicologo
una feminine nouns starting with a consonant una casa (a house), una penna (a pen), una ragazza (a girl)
un' feminine nouns starting with a vowel un'amica (a female friend), un'idea (an idea), un'ora (an hour)

Look at the gender first (see Noun gender), then at the first sound of the noun.

un or uno?

Both are masculine. uno is for the noun beginnings that are harder to say after un:

  • s + consonant: uno studente, uno specchio (a mirror), uno sport
  • z: uno zaino, uno zio (an uncle)
  • gn, ps, pn: uno gnocco, uno psicologo, uno pneumatico (a tyre)
  • x, y (rare): uno xilofono, uno yogurt

Masculine nouns with any other beginning take un: un libro, un gatto, un amico, un uomo.

un' only for feminine nouns

Before a vowel, una usually becomes un' (with an apostrophe): un'amica, un'idea. The masculine un never takes an apostrophe: ✅ un amico, ❌ un'amico. That apostrophe is what shows a feminine noun.

When to use it

  • To introduce something new or non-specific: C'è un ristorante qui vicino. (There's a restaurant near here.)
  • To say "one" of something: Ho un fratello e una sorella. (I have one brother and one sister.)
  • With a profession that is described or highlighted: Marco è un medico bravissimo. (Marco is a very good doctor.)

After essere, a bare profession usually has no article (Sono medico, see The verb "essere"); when the profession is described or highlighted, un / una often appears.

Italian does not use the indefinite article in expressions with avere such as Ho fame, Ho sete (see The verb "avere").

Plural: there is no plural indefinite article

un libro has no plural form of "a". For "some", Italian uses the partitive (dei libri), which has its own lesson: Partitive articles. The plural of nouns is in Plural nouns.

Common mistakes

  • ❌ un studente → ✅ uno studente (masculine before s + consonant)
  • ❌ un zaino → ✅ uno zaino (masculine before z)
  • ❌ un'amico → ✅ un amico (masculine never takes the apostrophe)
  • ❌ uno libro → ✅ un libro (uno is only for the special beginnings)
  • ❌ un casa → ✅ una casa (feminine takes una)

Quick check

Choose the right indefinite article.

  1. ____ ragazzo
  2. ____ studente
  3. ____ casa
  4. ____ amica
  5. ____ zaino
  6. ____ idea
Show answers
  1. un   2. uno   3. una   4. un'   5. uno   6. un'

Key takeaways

  • The indefinite article means "a / an / one": un, uno, una, un'.
  • un for most masculine nouns, uno for masculine nouns starting with s + consonant, z, gn, ps, pn, x or y.
  • una for feminine nouns before a consonant, un' before a vowel.
  • The masculine un never takes an apostrophe.
  • There is no plural indefinite article; "some" uses the partitive.