Sphaira

Part of speech: noun

Definitions

1. A term originating from Greek referring to a sphere or rounded object; a complete, symmetrical three-dimensional shape where all points are equidistant from the center; a geometric solid often used in mathematics and physics to describe round bodies
2. Describing a perfectly round three-dimensional figure with uniform curvature; an ancient word denoting any globe-like object; a shape characterized by its smooth, continuous surface equidistant from a central point
3. An ancient expression for a ball-shaped figure; a three-dimensional geometry concept representing an object with every location on its surface equally distant from its midpoint; a common form found in natural and artificial spheres alike

Etymology: Ancient Greek "sphaira" meant a ball, a playing ball, or a globe, and its root is probably the same as the one in "sphaírein", "to throw" or "to roll". Its oldest famous use is in Plato's writing, where he describes the cosmos as a sphere, and the word was taken up by Greek geometers, who defined a sphere as a solid bounded by a single curved surface, every point of which is equally distant from a centre. Euclid's "Elements" and later works relied on this idea. The word passed into Latin as "sphaera", and from there into Old French as "sphere", which reached English in the Middle Ages. English speakers used it for the celestial spheres of medieval astronomy, the nested crystalline shells believed to carry the planets and stars around the Earth, before it came to mean any perfectly round solid. The Greek form survives in its original spelling mainly in technical and scholarly writing about geometry.

Synonyms: sphere, ball, globe

Antonyms: cube, block