Design Nomenclature / Physical Model Making
Thermoforming
Also called sheet forming, drape forming, pressure forming
The whole family of processes that soften sheet plastic with heat and shape it against a tool — by vacuum, by air pressure, between matched dies, or draped over a form under its own weight. Vacuum forming is one member. The constant: thickness comes from the starting sheet and only ever decreases where the material stretches.
In practice
Every vacuum former is a thermoformer; not every thermoformer pulls vacuum. Shops use the words interchangeably and usually just mean the box in the corner.