late 14c., "act of reserving," from Old French reservation (14c.) and directly from Late Latin reservationem (nominative reservatio), noun of action from past participle stem of Latin reservare (see reserve, n.). Mental sense is from c.1600. U.S. sense "tract of public land set aside for some special use" is recorded from 1789, originally in reference to the Six Nations in New York State. Meaning "act or fact of engaging a room, a seat, etc." is from 1904, originally American English.