A name (or variation of a name) used by the French Romancers. As such, his name means "Perceval the Welsh." (Galois--"G" replacing "W," which doesn't exist in French: Galois-Wales). It's significant that Perceval is always Welsh, as there has been a good deal of debate whether the Grail romances are originally French or Celtic. These days, most scholars say it is Celtic, with a possible lost text that predates Chretien de Troyes.