echinus

[ih-kahy-nuh s] /ɪˈkaɪ nəs/
noun, plural echini
[ih-kahy-nahy] /ɪˈkaɪ naɪ/ (Show IPA)
1.
any sea urchin of the genus Echinus.
2.
Architecture.
  1. an ovolo molding, especially one having an outline with several radii or one carved with an egg-and-dart pattern.
  2. the prominent circular molding supporting the abacus of a Doric or Tuscan capital.
  3. Also called cymatium. the circular molding, usually carved with an egg-and-dart pattern, forming part of an Ionic capital between the volutes and under the balteus.
Origin
1325-75; Middle English < Latin < Greek echînos hedgehog, sea urchin
British Dictionary definitions for echinus

echinus

/ɪˈkaɪnəs/
noun (pl) -ni (-naɪ)
1.
(architect) an ovolo moulding between the shaft and the abacus of a Doric column
2.
any of the sea urchins of the genus Echinus, such as E. esculentus (edible sea urchin) of the Mediterranean
Word Origin
C14: from Latin, from Greek ekhinos