üliplastses olekus lehtmetalli (pleki) ja termoplastide vormimine gaasi normaalrõhul vaakumi moodustumisega matriitsiõõnes (vt termovormimine; vrd pneumovormimine, mehaaniline termovormimine), shaping a preheated thermoplastic or superplastic metal sheet by means of negative pressure (vacuum) to draw preheated material sheet into a mold cavity (see: thermoforming; compare: pressure thermoforming; mechanical thermoforming)