Concise Bible Dictionary:
This is literally “child conductor,” pedagogue: originally a slave who took his master’s children to school. The law was a schoolmaster to the Jews (not to the Gentiles: Paul said we, in contrast to ye in Gal. 3:26) until Christ came; but any led to Christ were no longer under that schoolmaster (Gal. 3:24-25; compare Rom. 6:14).
Strong’s Dictionary of Greek Words:
Transliteration:
paidagogos
Meaning:
from 3816 and a reduplicated form of 71; a boy-leader, i.e. a servant whose office it was to take the children to school; (by implication, (figuratively) a tutor ("paedagogue"))
KJV Usage:
instructor, schoolmaster