c.1400, "a pledge, vow," from Old French promesse "promise, guarantee, assurance" (13c.) and directly from Latin promissum "a promise," noun use of neuter past participle of promittere "send forth; let go; foretell; assure beforehand, promise," from pro- "before" (see pro-) + mittere "to put, send" (see mission). The ground sense is "declaration made about the future, about some act to be done or not done."

c.1400, from promise, n.. Related: Promised; promising. Promised land (1530s) is a reference to the land of Canaan promised to Abraham and his progeny (Hebrew xi:9, etc.; Greek ten ges tes epangelias).