From Britain and lake
A modern American invention, Britlyn combines the geographic name Brit (referring to Britain) with the popular suffix -lyn, which is derived from the Welsh word for lake. It follows the trend of creating new, melodic names by blending traditional elements.
Less common today
Britlyn isn't in the latest US Top 1000. It last peaked at #8,389 in 1990.
US births per 5-year period, 1990βpresent (SSA data).