Ordinal numbers 1st to 10th (primero, segundo, tercero)

Ordinal Numbers (1st to 10th)

Ordinal numbers show order or rank. In Spanish, they usually go before the noun and agree in gender and number.

NumberOrdinalNumberOrdinal
1stprimero6thsexto
2ndsegundo7thséptimo
3rdtercero8thoctavo
4thcuarto9thnoveno
5thquinto10thdécimo

Like other adjectives, they change their ending to -a for feminine nouns:

The second car is blue.
El segundo carro es azul.
The ninth class is difficult.
La novena clase es difícil.

Dropping the "-o" (primer and tercer)

Primero (1st) and tercero (3rd) drop their final -o when placed directly before a masculine singular noun, becoming primer and tercer.

He is the first student.
Él es el primer estudiante.
My office is on the third floor.
Mi oficina está en el tercer piso.

If the noun is feminine, they follow the normal rule (primera, tercera). If used on their own without a noun directly after them, they keep the -o.

You are the first and I am the tenth.
Tú eres el primero y yo soy el décimo.

Floors and Sequences

Ordinals are commonly used to talk about the floors of a building, days in a sequence, or specific events.

The seventh day of the week is Sunday.
El séptimo día de la semana es el domingo.
The second class is on the ninth floor.
La segunda clase es en el noveno piso.