The name is derived from the medieval Hungarian name Kósa (hypocoristic form of a given name beginning with Ko-, e.g. Konrád ‘Conrad’, Kornél ‘Cornelius’, Kozma ‘Cosmas’). It may also be derived from the given name Kósa (derived from the Hungarian common noun kos meaning ‘ram’ with the suffix -a). In both cases, it refers to the connection with the father or another ancestor by that name. Variants: Kosa, Kossa.