Addilyn is a modern American spelling of Adeline, which goes back through French to the Germanic adal and means "noble". It arose in the 2000s together with Adalyn, Adalynn and Adelyn as parents looked for fresh ways to reach the nickname Addie. In the United States Addilyn entered the top 1000 in 2010 and peaked at number 312 in 2016; it has since fallen to number 988 in 2025.