Diesel ranks at #167 with 615 entries, and the name belongs to a specific aesthetic register that was not really available before the early 2000s. It is in the same family as Harley, Tank, and Mack — mechanical or vehicular names that read as modern American working-dog texture.
The working-class male-dog aesthetic
Diesel is rarely used for cats and rarely used for female dogs. The name signals a particular kind of large, short-coated, often muscular dog — Pit Bulls, Boxers, Rottweilers, large mixed breeds. Owners who pick Diesel are almost always picking it for the tough-but-lovable register, and the name reads as affectionate within that aesthetic rather than aggressive. Compare with Tank, which sits in the same vehicular-male cluster.
One counter-reading: Diesel does occasionally land on small dogs as deliberate irony, similar to Spike. A 7-pound Chihuahua named Diesel is doing the same comedic work as a 90-pound Mastiff named Tiny. The naming joke depends on the audience knowing the original register, which means Diesel functions as cultural shorthand even when used ironically.
Why this name does not cross to babies
Vehicular names rarely make the SSA chart in any meaningful way, and Diesel is no exception. The name reads as too on-the-nose for human use in most American naming conventions, which leaves the entire cultural slot open for pets. The same dynamic applies to Tank and Harley, both of which sit nearby on the leaderboard in the male working-dog cluster. Owners who pick Diesel rarely consider those alternatives interchangeable; the specific word matters and signals a particular set of preferences.