convex

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Having a surface or boundary that curves or bulges outward, as the exterior of a sphere.

from The Century Dictionary.

• In geometry, having no reëntrant angle.
• Curved, as a line or surface, in the manner of a circle or sphere when viewed from some point without it; curved away from the point of view; hence, bounded by such a line or surface: as, a convex mirror.
• Specifically In zöol. and anatomy, elevated and regularly rounded; forming a segment of a sphere, or nearly so: distinguished from gibbous, which is applied to a less regular elevation.
• noun [⟨ L. convexum, prop. neut. of convexus, adj.: see above.] A convex body or surface.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Rising or swelling into a spherical or rounded form; regularly protuberant or bulging; -- said of a spherical surface or curved line when viewed from without, in opposition to concave.
• adjective convex on both sides; convexo-convex.
• noun A convex body or surface.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective curved or bowed outward like the outside of a bowl or sphere or circle
• adjective mathematics, not comparable (Of a set of points) such that for any two points in the set, every point between those two points is also in the set
• adjective analysis, not comparable (of a real-valued function on the reals) such that the value at any point, is no larger than the interpolated value thereat, based on the values at any two points between which the first point is contained
• noun Any convex body or surface.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective curving or bulging outward