at three o'clock
I can come at three.
Los clientes entran a las tres de la mañana a comprar carne.
Customers come in at three in the morning to buy meat.
— Fallen angels (Ángeles caídos) (1995)
I'll call you at three.
See you at three.
Te veo en el vestíbulo a las tres.
I'll see you in the lobby at three.