What defines a line segment?

A line segment is accurately defined as a portion of a line that has two definite endpoints. This characteristic is essential because it distinguishes a line segment from other geometric concepts, such as lines and rays. A line extends infinitely in both directions and does not have endpoints, while a ray has one endpoint and extends infinitely in one direction. The existence of endpoints means that a line segment has a measurable length and can be represented visually as the straight path connecting the two endpoints. This definition underpins many mathematical concepts, such as measurement, geometry, and spatial reasoning, making it foundational for students in grades 1-6.