Where does the name Ironless come from?

Where does the name Ironless come from?

Ironless linear motors are constructed, as their name suggests, without iron in the primary part (coil unit). The coils of the primary are embedded in a nonmagnetic core, and the secondary is typically u-shaped, with two magnet plates facing each other (also called a magnet yoke). The ironless coil unit moves in the space between the plates.

Because there is no iron in the coil unit, there are no attractive forces between the coil unit and the magnet plates.