[avar]

The word pragma in perl has always been used to refer to that specific syntax sugar, just read the start of "perldoc perlpragma".

Furthermore the $^H (there's also %^H) facility you mention is just one way pragmas are implemented, e.g. "use overload" is a core pragma that doesn't use that method at all, instead it defines special functions in the importing package which the compiler is aware of.

Then there are other "pragmas" that are really just utility wrapper functions, e.g. "use autouse". The "Pragmatic modules" section of "perldoc perlmodlib" has the full list.