The word graal, as it is earliest spelled, comes from Old French graal or greal, cognate with Old Provençal grazal and Old Catalan gresal, meaning "a cup or bowl of earth, wood, or metal" (or other various types of vessels in different Occitan dialects). The most commonly accepted etymology derives it from Latin gradalis or gradale via an earlier form, cratalis, a derivative of crater or cratus, which was, in turn, borrowed from Greek krater (κρατήρ, a large wine-mixing vessel). Alternative suggestions include a derivative of cratis, a name for a type of woven basket that came to refer to a dish, or a derivative of Latin gradus meaning "'by degree', 'by stages', applied to a dish brought to the table in different stages or services during a meal".
Late medieval writers such as Thomas Malory invented a fanciful new etymology for Old French san-graal (or san-gréal), meaning "Holy Grail", by parsing it as sang real, meaning "royal blood". After the cycle of Grail romances was well established, later writers used this alternative etymology. Since then, "Sang real" is sometimes employed to lend a medievalising air in referring to the Holy Grail. This connection with royal blood bore fruit in a modern bestseller linking many historical conspiracy theories (see § Modern interpretations below).