Käti / Kati / Katy / Katie

Käti is a diminutive form of names like Katherine or Katarina. The name Katherine itself derives from the Greek name Aikaterine. The etymology of Aikaterine is debated, but the most widely accepted theory links it to the Greek word 'katharos', meaning 'pure'. The name gained immense popularity through Saint Catherine of Alexandria, a 4th-century Christian martyr, whose veneration spread throughout Europe during the Middle Ages.

Over centuries, Katherine evolved into numerous forms across different languages. Käti is a more modern, often Finnish or Estonian, diminutive or pet form, reflecting a trend of shortening longer names while retaining a sense of endearment. Its usage is typically informal but can also be found as a given name in its own right.