Alistair is the Scottish Gaelic form of Alexander, and it carries a particular kind of old-world dignity that's become fashionable in pet naming as owners look for names with genuine etymology rather than invented whimsy. It's the name of a country house, a distinguished professor, or a dog who considers himself the rightful head of the household and acts accordingly.
Scottish Heritage in Pet Naming
Scottish names have found a reliable niche in dog naming — partly because Scottish terrier breeds make the connection literal, and partly because Scottish naming aesthetics (dignified, literary, slightly unpronounceable to outsiders) appeal to a specific type of owner. Scottish Terriers and Westies carry Alistair with particular coherence. The human name Alistair has genuine baby name usage in the UK, giving it additional legitimacy as a crossover choice.
The Dark Academia Aesthetic
Alistair fits the dark academia naming trend that brought names like Cornelius, Atticus, and Archibald back into pet naming conversations. Owners who read Victorian novels and drink Earl Grey tend to gravitate toward it. The -air ending gives it a slight lift that prevents it from being too heavy, balancing the gravitas with something almost musical. See Archibald for a comparable choice in the same register.
The Counter-Reading: Spelling Variants Create Fragmentation
Alistair, Alastair, Alasdair — the name has multiple legitimate spellings across Scottish, Irish, and English conventions. Owners who choose one will routinely have others substituted by people who know a different variant. This is a minor friction, but it's worth knowing that no single spelling is definitively "correct."