1630s, "one who enforces order;" see discipline; it was earlier used (often with capital D-) of Puritans who wanted to establish the Presbyterian "discipline" in England (1580s). An earlier word in the sense "enforcer of discipline" was discipliner (mid-15c.). Meaning "advocate of greater discipline" is from 1746.
c. 1300, disciplinen, "to subject to (penitential) discipline, correct, chastise, punish," from Old French descepliner and directly from Medieval Latin disciplinare, from Latin disciplina (see discipline (n.)). Meaning "instruct, educate, train" is from late 14c. Related: Disciplined; disciplines; disciplining.
Old English discipul (fem. discipula), "one who follows another for the purpose of learning," especially "the personal followers of Jesus Christ during his life, the twelve Apostles chosen or called by him to be his immediate associates," a Biblical borrowing from Latin discipulus "pupil, student, follower," which is of uncertain origin.
In OED and Watkins it is said to be from discere "to learn," from a reduplicated form of the PIE root *dek- "to take, accept." But according to Barnhart and Klein, it is from a lost compound *discipere "to grasp intellectually, analyze thoroughly," from dis- "apart" (see dis-) + capere "to take, take hold of," from PIE root *kap- "to grasp." De Vaan finds the ending -pulus "difficult to explain" in the former theory and the latter "semantically not compelling."
It was not common in Old English, where the usual word was leorningcniht, and in some cases þegn (see thane). The pre-Christian Latin sense of "scholar, pupil, student" is rare in English. Meaning "one who follows or is influenced by the doctrine or example of another" is from c. 1300.
c. 1200, "penitential chastisement; punishment for the sake of correction," from Old French descepline "discipline, physical punishment; teaching; suffering; martyrdom" (11c., Modern French discipline) and directly from Latin disciplina "instruction given, teaching, learning, knowledge," also "object of instruction, knowledge, science, military discipline," from discipulus "pupil, student, follower" (see disciple (n.)).
The Latin word is glossed in Old English by þeodscipe. The meaning "treatment that corrects or punishes" is from the notion of "order necessary for instruction."
Meaning "branch of instruction or education" is first recorded late 14c. Meaning "system of rules and regulations" is from mid-14c. Meaning "military training" is from late 15c., via the notion of "training to follow orders and act in accordance with rules;" that of "orderly conduct as a result of training" is from c. 1500. Sense of "system by which the practice of a church is regulated, laws which bind the subjects of a church in their conduct" is from 1570s.
"promoting orderly observance of rules," 1590s, from Medieval Latin disciplinarius, from Latin disciplina "instruction given, teaching," also "military discipline" (see discipline (n.)).
1610s, "one who subjects himself to a course of discipline," from Spanish Disciplinantes, name of a former religious order whose members scourged themselves in public, from Latin disciplina (see discipline (n.)).