Addelyn is a modern American spelling of Adalyn and Adeline, which go back to the Germanic adal and mean "noble" or "of noble kind". The doubled d ties it to the nickname Addie and to Addison, which was a top 20 name while Addelyn was at its height. In the United States Addelyn peaked at number 1175 in 2015 and has eased to number 2017 in 2025 with 94 births.