Why is the ninth month called September?
Old English discipul (fem. discipula), Biblical borrowing from Latin discipulus "pupil, student, follower," said to be from discere "to learn" [OED, Watkins], from a reduplicated form of PIE root *dek- "to take, accept" (see decent).
But according to Barnhart and Klein, from a lost compound *discipere "to grasp intellectually, analyze thoroughly," from dis- "apart" (see dis-) + capere "to take, take hold of" (see capable). Cf. Latin capulus "handle" from capere. Sometimes glossed in Old English by þegn (see thane).
a scholar, sometimes applied to the followers of John the Baptist (Matt. 9:14), and of the Pharisees (22:16), but principally to the followers of Christ. A disciple of Christ is one who (1) believes his doctrine, (2) rests on his sacrifice, (3) imbibes his spirit, and (4) imitates his example (Matt. 10:24; Luke 14:26, 27, 33; John 6:69).