Emily Dickinson Lexicon

DIS-CI-PLIN-A'RI-AN, n.

1. One who disciplines; one versed in rules, principles and practice, and who teaches them with precision; particularly, one who instructs in military and naval tactics and maneuvers. It is chiefly used in the latter sense, and especially for one who is well versed in, or teaches with exactness, military exercises and evolutions.
2. A puritan or presbyterian; so called from his rigid adherence to religious discipline. – Sanderson. [I believe not now used.]