Circle
A circle is a simple geometric shape in which all sides are equidistant from the center.  In navigation, a starship's heading was given in measurements called s (°), where 360° forms a full circle. ()

When James T. Kirk, Leonard McCoy and Hikaru Sulu were confronted by holograms of  in 2269 on the Kalandan outpost, each of the holograms where specifically designated to one of each of the men. To battle this, Kirk formulated the defense of having the three of them "form a circle", to avoid her touch. ()

While investigating a Dyson sphere in 2369, the sensors of the  indicated that the large circle they had found was a portal or airlock leading to the interior of the sphere. ()

In one of Miles O'Brien's memories of being in an Argrathi prison, he was taught by Ee'char how to draw geometric patterns called Eseekas. In explaining how to draw these patterns, Eechar demonstrated to O'Brien that they "[s]tart by drawing a circle" [...] then "gaze into the circle" and "relax your mind." Eechar continued, "[i]magine that the circle encompasses your whole existence. Let it become a part of you. Now without thinking, allow your hand to make a mark inside the circle. Now expand on the mark. Let it grow organically until it becomes a pattern." ()

See also 
 Circular course
 Circular orbit
 Cycle
 Sphere

External link 
 
Mathematics