\E*chi"nus\, n.; pl. {Echini}. [L., a hedgehog, sea
urchin, Gr. ?.]
1. (Zo["o]l.) A hedgehog.
2. (Zo["o]l.) A genus of echinoderms, including the common
   edible sea urchin of Europe.
3. (Arch.)
   (a) The rounded molding forming the bell of the capital of
       the Grecian Doric style, which is of a peculiar
       elastic curve. See {Entablature}.
   (b) The quarter-round molding (ovolo) of the Roman Doric
       style. See Illust. of {Column}
   (c) A name sometimes given to the egg and anchor or egg
       and dart molding, because that ornament is often
       identified with Roman Doric capital. The name probably
       alludes to the shape of the shell of the sea urchin.