Definition of vow

• n. - A solemn promise made to God, or to some deity; an act by which one consecrates or devotes himself, absolutely or conditionally, wholly or in part, for a longer or shorter time, to some act, service, or condition; a devotion of one's possessions; as, a baptismal vow; a vow of poverty.
• n. - Specifically, a promise of fidelity; a pledge of love or affection; as, the marriage vow.
• n. - To give, consecrate, or dedicate to God, or to some deity, by a solemn promise; to devote; to promise solemnly.
• n. - To assert solemnly; to asseverate.
• v. i. - To make a vow, or solemn promise.