Chokyo means "discipline" in the sense of punishment. Its direct translation is "training" (or "breaking" of an animal). In the case of erotic bondage, Chokyo is erotic discipline.
Chokyoshi (調教師) is an animal trainer, and kinbaku chokyoshi and chokyoshi are used as a role in SM play.
Chokyo is translated as "teacher" in the SM Teacher Hitomi" (『SM調教師瞳』) series.