1911 Encyclopædia Britannica/Echinus

ECHINUS (Gr. for “hedge-hog” or “sea-urchin”), in architecture, the convex moulding which supports the abacus of the Doric column. The term is sometimes given to the ovolo of the Ionic capital, especially when curved with the egg-and-tongue enrichment. The origin of this use of the word in architecture, which comes down from ancient times, is uncertain.