Tilda is a Scandinavian and German short form of Matilda, from the Old High German meaning "battle strength." On a female dog, it has a crisp, Northern European quality that sits in a different register from the Bella-Luna mainstream: distinctive without being obscure, short without being clipped.
The Tilda Swinton Effect
Tilda Swinton, the Scottish actress known for otherworldly, androgynous roles in films like Orlando, We Need to Talk About Kevin, and the Marvel films, is the most famous Tilda in current cultural life. She brings an avant-garde, unconventional quality to the name that owners may consciously or unconsciously invoke when choosing it for a female pet. A cat named Tilda is particularly easy to imagine.
The Matilda Connection
Tilda also connects to the Matilda tradition (Roald Dahl's 1988 novel, the beloved musical adaptation), giving it a literary-children's-book layer alongside the high art cinema association. The human name Tilda has been quietly growing in American use since 2015.
Breed Fit
Tilda works beautifully for independent, slightly aloof female breeds: Norwegian Elkhounds, Swedish Vallhunds, or any Scandinavian breed where the name has geographic coherence. It also works simply for a cat who acts like she knows more than you do.