Kaja

Kaja grew out of Katarzyna, the long Polish form, worn down over generations into two short syllables. As a form it follows a Slavic habit of trimming a name to a soft, easy sound. The name travels light.

The sense of "pure" came to Kaja later, on loan from the Greek behind Katarzyna, where the word katharos meant clean or clear. So the meaning sits one step removed, inherited from the fuller name rather than built into this short one. Many people who carry Kaja meet the longer Katarzyna only on official paper, and go by the short form everywhere else.

In a school class register, Kaja can sit a few lines from a Katarzyna, a nickname that hardened into a given name of its own. Polish readers gloss it warmly, as ciesząca rodziców, the one who gladdens her parents.