Main entry: round, circular
Definition: having a circular shape
Antonyms: square
Definition: having four equal sides and four right angles or forming a right angle
Antonyms: nonspherical
Definition: not spherical
Main entry: rotary, orbitual, circular
Definition: describing a circle; moving in a circle
Usage: the circular motion of the wheel
Antonyms: noncyclic, noncyclical
Definition: not cyclic
Antonyms: acyclic, open-chain
Definition: having an open chain structure
Antonyms: acyclic
Definition: not cyclic; especially having parts arranged in spirals rather than whorls