Freckled or broken land
A modern American invention likely combining the Scottish surname Breck, meaning 'freckled', with the popular suffix -lynn. It may also be inspired by the town of Breckenridge or the word 'breck', referring to broken or uncultivated land.
Less common today
Brecklynn isn't in the latest US Top 1000. It last peaked at #5,129 in 2018.
US births per 5-year period, 1990βpresent (SSA data).