Annulet

Webster's Dictionary

(1): (n.) A narrow circle of some distinct color on a surface or round an organ.

(2): (n.) A little circle borne as a charge.

(3): (n.) A little ring.

(4): (n.) A small, flat fillet, encircling a column, etc., used by itself, or with other moldings. It is used, several times repeated, under the Doric capital.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature

(a little ring) is a small, flat fillet encircling a column, etc., used either by itself or in connection with other mouldings. It is used, several times repeated, under the ovolo or echinus of the Doric capital.