Cove

A cove is a concave (inward-curving) molding profile, ranging from a shallow quarter-round scoop to a deep, dramatic hollow -- the visual and geometric opposite of a convex profile like a roundover or bullnose. It's cut with a cove router bit or shaper cutter of the matching radius, or, for wider coves than a standard bit offers, by running stock at an angle across a table saw blade -- a slower, more technique-dependent method, but capable of cutting coves far larger than most router bits can manage in one pass.

Cove profiles show up constantly in moulding and cornice work, either as a standalone edge treatment or combined with other profiles (a cove-and-bead, for instance) into a more elaborate composite shape.