Definition of: obligation

(ob′lə·gā′shən) noun
1. The act of obligating or state of being obligated; also, the duty, promise, etc., by which one is bound.
2. The constraining power of conscience or law.
3. A requirement imposed by the customs of society or the laws of propriety and expediency; what one owes in return for a service, benefit, kindness, favor, etc.
4. A binding legal agreement, contract, bond, etc., bearing a penalty.
5. The condition of being indebted for an act of kindness, a service received, etc.; also, the kindness or service. See synonyms under DUTY.
—ob′li·ga′tor noun