God will add
A modern American elaboration of Jocelyn or Josephine. It combines the Hebrew roots of Joseph, meaning 'He will add,' with the popular 'lynn' suffix, often associated with a lake or waterfall in Welsh contexts.
Less common today
Josilynn isn't in the latest US Top 1000. It last peaked at #6,268 in 2012.
US births per 5-year period, 1990βpresent (SSA data).