The Collaborative International Dictionary of English v.0.48:

Markov chain \Mark"ov chain\, n. [after A. A. Markov, Russian
   mathematician, b. 1856, d. 1922.] (Statistics)
   A random process (Markov process) in which the probabilities
   of discrete states in a series depend only on the properties
   of the immediately preceding state or the next preceeding
   state, independent of the path by which the preceding state
   was reached. It differs from the more general Markov process
   in that the states of a Markov chain are discrete rather than
   continuous. Certain physical processes, such as diffusion of
   a molecule in a fluid, are modelled as a Markov chain. See
   also random walk. [Also spelled Markoff chain.]
   [PJC]

WordNet (r) 3.0 (2006):

Markoff chain
    n 1: a Markov process for which the parameter is discrete time
         values [syn: Markov chain, Markoff chain]