Definitions

1. verb

to shape or form in advance, especially to create a mold or template for a product

“The engineer preformed the metal sheet to create a precise mold for the car part.”

2. noun

a mold or template used to shape a material in advance

“The machine uses a preform to shape the plastic bottle.”

3. verb (chiefly in materials science)

to cause (a material) to change its shape or form by heat and pressure, before it is given its final shape

“The molten glass is preformed to create the desired shape.”