Suppose a person is forced by law to serve a fixed time as a slave, before they are granted freedom. What would you call this arrangement?
It's not a contract or an agreement, because the slave does not necessarily agree to it. Arrangement is too soft and sentence too hard.
I guess a euphemism for sentence would do?
Just to put this in context, what I'm really after is a euphemistic way in which the slave's owner might refer to the finite duration of a slavery term
Geoffrey has three years left on his contract, after which I shall have to find a replacement
I'm starting to think "commitment" or "obligation" might suit better