Extrusion is a forming process used in ceramic manufacturing.
In this process, a stiff plastic ceramic mass is forced through a die.
The die has a fixed opening shape.
When the ceramic mass passes through the die, it comes out as a continuous column having uniform cross section.
This method is useful for making products such as pipes, tubes, rods, bricks, and tiles.
Throwing is done on a potter's wheel.
Jiggering is used for shaping ware on rotating moulds.
Slip casting uses liquid slip poured into plaster moulds.
Since the question says that a stiff plastic mass is forced through a nozzle and die, the process is:
\[
\text{Extrusion}.
\]