The Collaborative International Dictionary of English v.0.48:

Capability \Ca`pa*bil"i*ty\, n.; pl. Capabilities.
   1. The quality of being capable; capacity; capableness; esp.
      intellectual power or ability.
      [1913 Webster]

            A capability to take a thousand views of a subject.
                                                  --H. Taylor.
      [1913 Webster]

   2. Capacity of being used or improved.
      [1913 Webster]

WordNet (r) 3.0 (2006):

capability
    n 1: the quality of being capable -- physically or
         intellectually or legally; "he worked to the limits of his
         capability" [syn: capability, capableness] [ant:
         incapability, incapableness]
    2: the susceptibility of something to a particular treatment;
       "the capability of a metal to be fused" [syn: capability,
       capacity]
    3: an aptitude that may be developed [syn: capability,
       capableness, potentiality] [ant: incapability,
       incapableness]

The Free On-line Dictionary of Computing (19 January 2023):

capability

    An operating system security or
   access control model where specific types of access to a
   specific object are granted by giving a process this data
   structure or token.

   The token may be unforgeable (typically by using encryption
   or hardware "tagged" memory).  Capabilities are used in OSes
   such as Hydra, KeyKOS, EROS, Chorus/Mix, and the
   Stanford V system.  Similar to Kerberos, but in an OS
   context.

   Compare access control list.

   (1998-03-08)