The Collaborative International Dictionary of English v.0.48:

Capacity \Ca*pac"i*ty\ (k[.a]*p[a^]s"[i^]*t[y^]), n.; pl.
   Capacities (-t[i^]z). [L. capacitus, fr. capax, capacis;
   fr. F. capacit['e]. See Capacious.]
   1. The power of receiving or containing; extent of room or
      space; passive power; -- used in reference to physical
      things.
      [1913 Webster]

            Had our great palace the capacity
            To camp this host, we all would sup together.
                                                  --Shak.
      [1913 Webster]

            The capacity of the exhausted cylinder. --Boyle.
      [1913 Webster]

   2. The power of receiving and holding ideas, knowledge, etc.;
      the comprehensiveness of the mind; the receptive faculty;
      capability of understanding or feeling.
      [1913 Webster]

            Capacity is now properly limited to these [the mere
            passive operations of the mind]; its primary
            signification, which is literally room for, as well
            as its employment, favors this; although it can not
            be denied that there are examples of its usage in an
            active sense.                         --Sir W.
                                                  Hamilton.
      [1913 Webster]

   3. Ability; power pertaining to, or resulting from, the
      possession of strength, wealth, or talent; possibility of
      being or of doing.
      [1913 Webster]

            The capacity of blessing the people.  --Alex.
                                                  Hamilton.
      [1913 Webster]

            A cause with such capacities endued.  --Blackmore.
      [1913 Webster]

   4. Outward condition or circumstances; occupation;
      profession; character; position; as, to work in the
      capacity of a mason or a carpenter.
      [1913 Webster]

   5. (Law) Legal or moral qualification, as of age, residence,
      character, etc., necessary for certain purposes, as for
      holding office, for marrying, for making contracts, wills,
      etc.; legal power or right; competency.
      [1913 Webster]

   Capacity for heat, the power of absorbing heat. Substances
      differ in the amount of heat requisite to raise them a
      given number of thermometric degrees, and this difference
      is the measure of, or depends upon, what is called their
      capacity for heat. See Specific heat, under Heat.

   Syn: Ability; faculty; talent; capability; skill; efficiency;
        cleverness. See Ability.
        [1913 Webster]