Source : Webster's Revised Unabridged Dictionary (1913)

Registration \Reg`is*tra"tion\ (-tr?"sh?n), n. [LL. registratio,
   or F. r['e]gistration. See {Register}, v.]
   1. The act of registering; registry; enrollment.

   2. (Mus.) The art of selecting and combining the stops or
      registers of an organ.

Source : WordNet®

registration
     n 1: the act of enrolling [syn: {enrollment}, {enrolment}]
     2: the body of people (such as students) who register or enroll
        at the same time [syn: {enrollment}]
     3: a document certifying an act of registering
     4: (music) the sound property resulting from a combination of
        organ stops used to perform a particular piece of music;
        the technique of selecting and adjusting organ stops
     5: the act of adjusting something to match a standard [syn: {adjustment},
         {readjustment}]