fem. proper name, from French Catherine, from Medieval Latin Katerina, from Latin Ecaterina, from Greek Aikaterine. The -h- was introduced 16c., probably a folk etymology from Greek katharos "pure" (see catharsis). The initial Greek vowel is preserved in Russian form Ekaterina.
As the name of a type of pear, attested from 1640s. Catherine wheel (early 13c.) originally was the spiked wheel on which St. Catherine of Alexandria (martyred 307), legendary virgin from the time of Maximinus, was tortured and thus became the patron saint of spinners. Her name day is Nov. 25; a popular saint in the Middle Ages, which accounts for the enduring popularity of the given name. It was applied from 1760 to a kind of fireworks shooting from a revolving spiral tube.
<a href="https://www.etymonline.com/word/Caitlin">Etymology of Caitlin by etymonline</a>
Harper, D. (n.d.). Etymology of Caitlin. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/Caitlin