registration (n.)the act of enrolling;
registration (n.)the body of people (such as students) who register or enroll at the same time;
registration (n.)a document certifying an act of registering;
registration (n.)(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;
registration (n.)the act of adjusting something to match a standard;