Londyn is a modern American spelling of "London", the British capital, whose Roman name Londinium is of uncertain origin. The -yn ending aligns it with names like Brooklyn and Madelyn, turning the place name into something that looks unmistakably like a girl's name. Londyn appeared in the US top 1000 in 2007, peaked at number 154 in 2014 and has slipped to number 388 in 2025.