convex

American Heritage® Dictionary of the English Language, Fourth Edition

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

Century Dictionary and Cyclopedia

1. 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. A curved line or surface is regarded as convex when it falls between the point of view and a line joining any two of its points. See concave.
2. 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.
3. n. [⟨ L. convexum, prop. neut. of convexus, adj.: see above.] A convex body or surface.
4. In geometry, having no reëntrant angle.

Wiktionary

1. adj. curved or bowed outward like the outside of a bowl or sphere or circle
2. adj. 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
3. adj. 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
4. n. Any convex body or surface.

GNU Webster's 1913

1. adj. 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.
2. n. A convex body or surface.

WordNet 3.0

1. adj. curving or bulging outward