A follower of Christ
Kerstyn is a modern phonetic spelling variant of Kirsten, which is the Scandinavian form of Christina. It ultimately derives from the Latin name Christianus, meaning 'follower of Christ'. While the name has deep religious roots, this specific spelling is a contemporary American innovation.
Less common today
Kerstyn isn't in the latest US Top 1000. It last peaked at #3,703 in 1999.
US births per 5-year period, 1990βpresent (SSA data).