Definition:Segment


 * Geometry:
 * Segment of a Circle: The part of a circle cut off by a straight line that cuts the circle into two parts.
 * Line segment: a straight line whose endpoints are both defined.


 * Order theory:
 * (Initial) segment determined by an element: The set of all elements of a poset which precede that element. Usually seen in the context of:
 * Segment of a well-ordered set: The set of all elements of a woset smaller than a given element.