​OVOLO (adapted from Ital. uovolo, diminutive of uovo, an egg; other foreign equivalents are Fr. ove, échine, quart de rond; Lat. echinus), in architecture, a convex moulding known also as the echinus, which in Classic architecture was invariably carved with the egg and tongue. In Roman and Italian work the moulding is called by workmen a quarter round. It must not be confounded with the echinus of the Greek Doric capital, as this was of a more varied form and of much larger dimensions than the ovolo, which was only a subordinate moulding.