What is the meaning of Echinus?

A sea urchin.

The rounded moulding forming the bell of the capital of the Grecian Doric style, which is of a peculiar elastic curve.

The quarter-round moulding (ovolo) of the Roman Doric style.

The egg-and-anchor or egg-and-dart moulding, because often identified with the Roman Doric capital.

a sea urchin, especially the edible kind

a hedgehog

the prickly husk of a chestnut

a rinsing bowl, especially of copper

an ornament under the chapiter of an Ionic or Doric column

Source: wiktionary.org