From the gate; land of the gate
Gatlynn is a modern American invention, likely created by combining the English surname Gatlin with the popular feminine suffix -lynn. As a surname, Gatlin likely refers to a dweller by a gate or a companion. The addition of -lynn softens the name and aligns it with contemporary naming trends for girls.
Less common today
Gatlynn isn't in the latest US Top 1000. It last peaked at #9,618 in 2014.
US births per 5-year period, 1990βpresent (SSA data).