vs 

QUICK ANSWER
"Una" is a form of "una", a noun which is often translated as "one". "Diez" is a form of "diez", an adjective which is often translated as "ten". Learn more about the difference between "una" and "diez" below.
la una(
oo
-
nah
)
A feminine noun is almost always used with feminine articles and adjectives (e.g., la mujer bonita, la luna llena).
feminine noun
a. one
Es la una de la tarde.It's one in the afternoon.
b. one o'clock
Tengo una cita a la una.I have an appointment at one o'clock.
Copyright © 2025 Dictionary Media Group, Inc.
diez(
dyehs
)
An adjective is a word that describes a noun (e.g., the big dog).
adjective
a. ten
Solo había diez personas en la oficina hoy a causa de la nieve.There were only ten people in the office today because of the snow.
A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).
masculine noun
a. ten
Ella lleva un diez en su camiseta en honor a su jugadora favorita.She wears a ten on her jersey in honor of her favorite player.
b. tenth (in dates)
Celebraremos mi cumpleaños el diez de enero.We'll celebrate my birthday on the tenth of January.
Copyright © 2025 Dictionary Media Group, Inc.