The only free and comprehensive online etymological dictionary of the Spanish language
cada (Preposition) "each," "every"
10th cent. From Latin cata "by," from Ancient Greek κάτα (káta) "concerning;" "downwards." From Proto-Indo-European *km̥t- "down"
Indo-European
Romance
Asturian cada, Portuguese cada, Galician cada, Catalan cada, Romanian câte
Indo-Iranian
Hittite kattan "below"