They're special forms in a language where functions are something which eagerly evaluates its arguments.
In a language where functions don't do that, they're just functions. Rye appears to be one of those languages. One could quibble about whether that's the right thing to call them, but if we say they're vau or whatever, "everything in Rye is a vau" is still true. I think calling them functions is reasonable though.
In Kernel, we could argue that operatives are the more fundamental type of combiner, and applicatives (aka functions) are the sole special-form, constructed by calling `wrap` on another combiner.
In a language where functions don't do that, they're just functions. Rye appears to be one of those languages. One could quibble about whether that's the right thing to call them, but if we say they're vau or whatever, "everything in Rye is a vau" is still true. I think calling them functions is reasonable though.