at one o'clock
Tenemos una pausa de almuerzo de una hora desde las doce a la una.
We have a one-hour lunch break from twelve to one.
I went to bed at one.
A la una, a las dos, a las tres.
At one, at two, at three.
Puede que a la una de la madrugada.
Maybe at one in the morning.
At one o'clock.
I went to bed at one.