Source : Webster's Revised Unabridged Dictionary (1913)

Latency \La"ten*cy\, n. [See {Latent}.]
   The state or quality of being latent.

         To simplify the discussion, I shall distinguish three
         degrees of this latency.                 --Sir W.
                                                  Hamilton.

Source : WordNet®

latency
     n 1: (computer science) the time it takes for a specific block of
          data on a data track to rotate around to the read/write
          head [syn: {rotational latency}]
     2: the time that elapses between a stimulus and the response to
        it [syn: {reaction time}, {response time}, {latent period}]
     3: the state of being not yet evident or active

Source : Free On-Line Dictionary of Computing

latency
     
         1. The time it takes for a {packet} to cross
        a network connection, from sender to receiver.
     
        2. The period of time that a frame is held by a network device
        before it is forwarded.
     
        Two of the most important parameters of a communications
        channel are its latency, which should be low, and its
        {bandwidth}, which should be high.  Latency is particularly
        important for a {synchronous} {protocol} where each packet
        must be acknowledged before the next can be transmitted.
     
        (2000-02-27)