ILGUR: Italian Language, Grammar and Usage Resource

What are ordinal numbers (i numeri ordinali)?

Ordinal numbers are used to indicate order of succession, and they typically come before the noun they modify while following the definite article. They are adjectives and must agree in gender and number with the noun that they modify.

• primo = first
• secondo = second
• terzo = third
• quarto = fourth
• quinto = fifth
• sesto = sixth
• settimo = seventh
• ottavo = eighth
• nono = ninth
• decimo = tenth
• undicesimo = evelenth
• dodicesimo = twelfth
• tredicesimo = thirteenth
• quattordicesimo = fourteenth
• quindicesimo = fifteenth
• sedicesimo = sixteenth
• diciassettesimo = seventeenth
• diciottesimo = eighteenth
• diciannovesimo = nineteenth
• ventesimo = twentienth
• ventitreesimo = twenty-third
• ventiseiesimo = twenty-sixth
• centesimo = hundredth
• millesimo = thousandth

REMEMBER: Ordinal numbers that end in tre or sei retain their final vowel (see above!)

ALSO REMEMBER: That ordinal numbers are used to make fractions also. The numerator is typically a cardinal number (uno, due, tre, ecc) while the denominator is an ordinal number in the singular (when the numerator is 1) or plural (when the denominator is greater than 1):

• 1/3 = un terzo
• 4/5 = quatro quinti
• 3/8 = tre ottavi
• exception: 1/2 = un mezzo or una metà

ONE FINAL POINT: Don’t forget the ordinal number, ennesimo, which means ‘umpteenth’ or ‘nth’, which is used when the number is not known or when the number is exaggerated:

• È l’enessima volta che ho letto il capitolo!
  It is the umpteenth time that I have read this chapter.

LAST BUT NOT LEAST: Ordinal numbers can also be abbreviated like in English (1st, 2nd, 3rd, etc). Read more about that by clicking here.