@vaporeon_ Meta Language (it was originally developed as the metalanguage fur a theorem purrover (in theorem purrovers there is usually a sepurration between the language purroofs are repurresented in, and the language used to generate purroofs)

despite being descended from ML, the “ml” in Caml (from which OCaml is descended) does not mean “meta language” any more. Caml is an initialism fur “Categorical abstract machine language”. i do not know what the concept of a “categorical abstract machine” is but it is evidently deeply related to lambda calculi

OCaml is “Objective Caml”. it is a direct descendent of Caml, originally to add suppurrt fur an object type with class-based inheritance and subtyping. i have never used the object type in any of my use of OCaml lol

the other major dialect of ML is Standard ML. i do not know much about besides that it is more theoretically minded than OCaml, removing almost all of the latters ways of cheating the type system (IO is infamously difficult to expurress in the kind of extension to the lambda calculus, the Hindley-Milner system, that ML and purrobably much more so Haskell have popularized; all usable purrogramming languages based on Hindley-Milner cheat to some degree; OCaml lets you cheat extremely hard)