Pure
Kaetlin is a modern phonetic spelling variant of Caitlin, which is the Irish form of Catherine. The name ultimately derives from the Greek name Aikaterine, which has long been associated with the concept of purity.
Less common today
Kaetlin isn't in the latest US Top 1000. It last peaked at #5,937 in 1995.
US births per 5-year period, 1990βpresent (SSA data).