An Etymological Dictionary of Astronomy and Astrophysics

1. A branch of learning or instruction.
   

2. A system of rules for behavior, methods of practice, etc.
   

Etymology (EN): M.E., from M.Fr. discipline, descepline, from L. disciplina literally “teaching, instruction,” from discipulus “pupil, student, follower,” from dis- + cipere, combining form of capere “to take,” → concept, + -ulus, → -ule.

Etymology (PE): Hâvešân, from hâveš “disciple, pupil,” Mid.Pers. hâvišt “disciple, pupil;” Av. hāvišta- “disciple, pupil,” + -ân a suffix denoting “group, order, system.”