Kasaitis

The origin is unclear. Cf. (?) German Koβ, Kosse, etc. ¹. See also Kasẽlis. But the root ka- can also be from some baptismal name - Kostos, Konstantinos or something like thimm. This would also be confirmed by surnames with derived stems - Kasiukónis, Kasiùlis, Kasiū́nas (see), etc.