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"Tarde" is a form of "tarde", an adverb which is often translated as "late". "Día" is a noun which is often translated as "day". Learn more about the difference between "tarde" and "día" below.
tarde, la tarde(
tahr
-
deh
)An adverb is a word that describes a verb, an adjective, or other adverbs (e.g., to run quickly, very tired).
A feminine noun is almost always used with feminine articles and adjectives (e.g., la mujer bonita, la luna llena).
a. afternoon (from noon until sunset)
Esta tarde me voy de compras con mis amigas.I'm going shopping with my friends this afternoon.
b. evening (around sunset)
Te veré esta tarde después del trabajo.I'll see you this evening after work.
el día(
dee
-
ah
)A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).
a. day
Estoy en el restaurante en donde comimos el otro día.I'm at the restaurant where we ate the other day.
2. (daylight)
a. day
Los que trabajan en el turno de noche tienen que dormir de día.Night workers have to sleep during the day.