Messenger or angel
Gelina is likely a diminutive or variant of Angela or Angelina, which are derived from the Greek word 'angelos'. It conveys the concept of a divine messenger or a heavenly being. In some contexts, it is also associated with the Germanic element 'gel' meaning bright or shining.
Less common today
Gelina isn't in the latest US Top 1000. It last peaked at #12,300 in 2006.
US births per 5-year period, 1990βpresent (SSA data).