Unknown; possibly a modern variant of Caston or Karsten
The exact etymology of Kastin is unclear, as it is a rare modern name. It likely functions as a creative spelling of Caston, an English habitational surname, or Karsten, a Low German form of Christian meaning 'follower of Christ'. In some cases, it may be a purely phonetic invention combining popular sounds.
Less common today
Kastin isn't in the latest US Top 1000. It last peaked at #6,950 in 2015.
US births per 5-year period, 1990–present (SSA data).
