QUICK ANSWER
"A las cinco" is a phrase which is often translated as "at five", and "cuarto" is an adjective which is often translated as "fourth". Learn more about the difference between "a las cinco" and "cuarto" below.
a las cinco(
ah
lahs
seeng
-
koh
)A phrase is a group of words commonly used together (e.g., once upon a time).
a. at five
¿A qué hora sale el próximo tren para Boston? - El próximo a Boston sale a las cinco.What time does the next train to Boston leave? - The next Boston train leaves at five.
b. at five o'clock
¿Es verdad que los ingleses toman siempre el té a las cinco?Is it true that English people always have tea at five o'clock?
cuarto, el cuarto(
kwahr
-
toh
)An adjective is a word that describes a noun (e.g., the big dog).
a. fourth
Entra al edificio y toma el ascensor al cuarto piso.Enter the building and take the elevator to the fourth floor.
A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).