Definition of circle:

part of speech: verb

To move round; to encompass; to surround or enclose; to keep together.

part of speech: noun

A figure contained by a single curved line called its circumference, every part of which is equally distant from a point within it called the centre; a ring; any round body; the compass or circuit of anything or place; a sphere or station in society; a number of persons, as a circle of friends; a series ending where it begins.