Egg-and-dart, also known as egg-and-tongue, egg and anchor, or egg and star, are terms that refer to an ornamental device adorning the fundamental quarter-round, convex ovolo profile of moulding, consisting of alternating details on the face of the ovolo—typically an egg-shaped object alternating with a V-shaped element (e.g., an arrow, anchor, or dart). The device is carved or otherwise fashioned into ovolos composed of wood, stone, plaster, or other materials.
Egg-and-dart enrichment of the ovolo molding of the Ionic capital was used by ancient Greek builders so it's found in ancient Greek architecture (e.g., the Erechtheion at the Acropolis of Athens), was used later by the Romans and continues to adorn capitals of modern buildings built in Classical styles (e.g., the Ionic capitals of the Jefferson Memorial in Washington, D.C.). The moulding design element continues in use in neoclassical architecture.