A follower of Christ
Keirstan is a modern phonetic variant of Kirsten, which is the Scandinavian form of Christina. It ultimately derives from the Latin name Christianus, meaning 'a follower of Christ'. While rare, this spelling emphasizes a contemporary American approach to traditional names.
Less common today
Keirstan isn't in the latest US Top 1000. It last peaked at #6,619 in 1995.
US births per 5-year period, 1990βpresent (SSA data).