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".
In the 15th century, English writer John Hardyng 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". This etymology was used by some later medieval British writers such as Thomas Malory, and became prominent in the conspiracy theory developed in the book The Holy Blood and the Holy Grail, in which sang real refers to the Jesus bloodline.