Whole, universal, or rival
Emmalin is a modern compound or variant of Emma and the suffix -line or -lyn. It likely derives from the Germanic 'ermen' meaning whole or universal, or potentially from the Latin Aemilia, meaning rival.
Less common today
Emmalin isn't in the latest US Top 1000. It last peaked at #2,426 in 2010.
US births per 5-year period, 1990βpresent (SSA data).