Concave :: Concave (a.) Hollow and curved or rounded; vaulted; -- said of the interior of a curved surface or line, as of the curve of the of the inner surface of an eggshell, in opposition to convex; as, a concave mirror; the concave arch of the sky..
Concavity :: Concavity (n.) A concave surface, or the space bounded by it; the state of being concave..
Concavo-concave :: Concavo-concave (a.) Concave or hollow on both sides; double concave.
Concavo-convex :: Concavo-convex (a.) Concave on one side and convex on the other, as an eggshell or a crescent..
Concavo-convex :: Concavo-convex (a.) Specifically, having such a combination of concave and convex sides as makes the focal axis the shortest line between them. See Illust. under Lens..
Convexo-concave :: Convexo-concave (a.) Convex on one side, and concave on the other. The curves of the convex and concave sides may be alike or may be different. See Meniscus..
Plano-concave :: Plano-concave (a.) Plane or flat on one side, and concave on the other; as, a plano-concave lens. See Lens..
Subconcave :: Subcompressed (a.) Not fully compressed; partially or somewhat compressed.