The ability to receive, hold, or absorb. A measure of this ability; volume. The maximum amount that can be contained: a trunk filled to capacity. Ability to perform or produce; capability. The maximum or optimum amount that can be produced: factories operating below capacity. The power to learn or retain knowledge; mental ability. Innate potential for growth, development, or accomplishment; faculty. See Synonyms at ability. The quality of being suitable for or receptive to specified treatment: the capacity of elastic to be stretched. The position in which one functions; role: in your capacity as sales manager. Legal qualification or authority: the capacity to make an arrest. Electricity Capacitance. Filling a space with the most it can hold: a capacity crowd at the concert.