1. (Zoology) either of a pair of sensory appendages that arise from the mouthparts of crustaceans and insects. 2. (Zoology) either of a pair of tactile organs arising from the head or anterior end of certain annelids and molluscs. [C19: from French, from Latin palpus a touching]
Convex, meaning curving out or extending outward (compare concave), may refer to: Convex set in mathematics Convex function in mathematics convex polygon a polygon in which no line segment between two points on the boundary ever goes outside the polygon.
A convex lens is thicker at the centre than at the edges. Convex lenses are thicker at the middle. Rays of light that pass through the lens are brought closer together (they converge). A convex lens is a converging lens. When parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus. The distance between the principal focus and the centre of the lens is called the focal length.