camber

camber is a Noun

Definition:

[1] An upward convexity of a deck or other surface; as, she has a high camber (said of a vessel having an unusual convexity of deck).

[2] An upward concavity in the under side of a beam, girder, or lintel; also, a slight upward concavity in a straight arch. See Hogback. Camber arch (Arch.), an arch whose intrados, though apparently straight, has a slightly concave curve upward. -- Camber beam (Arch.), a beam whose under side has a concave curve upward.