It’s an English expression that can mean two things even though it’s the same thing.
Once upon a time, children of poor parents were “bound out” to a wealthier family.
This is both:
Indentured servitude, which is a form of slavery with a possible escape clause
apprenticeship to a functional trade, such as housework, machinist, carpenter, etc.
You can see it as a form of adoption (think: Oliver Twist)
Punishing poor parents by abducting their children as labor.
Oddly, it’s not an either/or thing. It really is both.