Very early 12th cent. Old Spanish egual. From Latin æqualis 'id.,' composed of æquus "equal" and -alis, an adjective-forming suffix indicating a relationship (see -al (2)).
Latin æquus is of unknown origin.
Romance: Western Vulgar Latin: Asturian igual, Portuguese igual, Galician igual, Catalan igual, French égal, Italian uguale; Eastern Vulgar Latin: Romanian egal; Sardinian: aguale