What is the meaning of Murex?

Any of the genus Murex of marine gastropods.

Murex

A shellfish used as a source of the dye Tyrian purple; the purple-fish

Tyrian purple, the purple dye, a purple color, made from the juice of the purple-fish

A sharp murex shell used as a bridle bit.

A pointed rock or stone.

A caltrop.

An iron spike.

Source: wiktionary.org