Echinus
ECHINUS , 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.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)