Modern spelling variant of Adeline, from Germanic Adalheidis meaning 'noble kind' or 'of noble nature.'
Addelynn is a contemporary spelling elaboration of Adeline, which itself descends from the Old High German Adalind, a compound of adal (noble) and lind (soft, tender, or serpent — a symbol of wisdom and renewal in Germanic heraldry). The root adal is extraordinarily productive in European naming history, giving rise to Adolf, Adelaide, Adela, Alice, and dozens of other names that spread across the continent with Frankish and Norman aristocracy. Adeline was a favored name among medieval European nobility and retained quiet dignity through subsequent centuries.
The nineteenth century saw Adeline flourish anew on both sides of the Atlantic, immortalized in the 1903 barbershop standard "Sweet Adeline (You're the Flower of My Heart)," which cemented the name's warm, sentimental associations for generations. In the twentieth century it receded, carried mainly by grandmothers and great-grandmothers, before Adeline and its sister forms — Adaline, Adalynn, Adelyn — returned forcefully in the 2000s and 2010s on the wave of vintage revival naming. Addelynn represents the furthest elaboration of this revival wave, adding an extra D and a Y where earlier forms used an I.
This kind of creative respelling reflects a genuine cultural movement: parents who love the sound and history of a classic name but wish to give their child a typographically distinct version. The doubled D gives the name a slightly more emphatic, grounded feel on the page, while the -lynn ending aligns it with a generation of Carolynns, Madilyns, and Braylyns. Whatever the spelling, the name carries its ancient meaning — noble softness — intact.