I have also heard it as "gypsum wallboard", which is certainly most descriptive.

I'm not certain whether the water-resistant, mold-resistant variety typically hung behind tiles in bathrooms is ever referred to as "wetwall" or if they still call it "drywall".

Nor am I aware of whether anyone calls the foil-backed, glass-reinforced, fire-resistant variety "firewall" instead of "drywall".

I wouldn't be surprised if obsolete and inapplicable names still attach to items with the same function. If we ever move to polyethylene film panels sandwiched with phase-change material for our walls, it might still be called "plasterboard" somewhere.