echinus

Etymology

From Latin echīnus (“hedgehog; sea urchin”), from Ancient Greek ἐχῖνος (ekhînos).

noun

1. A sea urchin.
   'It is a sea-urchin - a common echinus. Nature repeats itself in many forms regardless of the size. This echinus is a model, a prototype, of the world.' 1929, Sir Arthur Conan Doyle, When the World Screamed
2. (architecture) The rounded moulding forming the bell of the capital of the Grecian Doric style, which is of a peculiar elastic curve.
3. (architecture) The quarter-round moulding (ovolo) of the Roman Doric style.
4. (architecture) The egg-and-anchor or egg-and-dart moulding, because often identified with the Roman Doric capital.