A straight line is the shortest distance between two points in a plane. It extends infinitely in both directions and has no curves or bends. In geometry, it is often represented by a line segment, which has two endpoints, or by a line that continues indefinitely. In mathematics, a straight line can be described using an equation, such as y = mx + b, where m is the slope and b is the y-intercept. Straight lines are fundamental in various fields, including physics, engineering, and computer graphics, as they help model relationships and create structures.