速端曲线图是一种线图，可以用来展示出物体或流体的矢量运动。这图所展现的曲线称为速端曲线，顾名思意，与速度有关。假若我们将速度矢量的尾部固定于坐标系统的原点，则速度矢量首部的轨迹是速端曲线。在曲在线，任何一点的径向距离 与移动的粒子的速率成正比。将这定义延伸，可以用来展示任意变量矢量的运动行为。

速端曲线图最先由威廉·卢云·哈密顿给予实际用途。于 1846 年，他在皇家爱尔兰学院院刊 (Proceedings of the Royal Irish Academy) 发表了一篇关于克卜勒问题的论文；其中，他用速端曲线来显示速度矢量首部的轨道，证明了这曲线是圆形。

A hodograph is a diagram that gives a vectorial visual representation of the movement of a body or a fluid. It is the locus of one end of a variable vector, with the other end fixed. The position of any plotted data on such a diagram is proportional to the velocity of the moving particle. It is also called a velocity diagram. It appears to have been used by James Bradley, but its practical development is mainly from Sir William Rowan Hamilton, who published an account of it in the Proceedings of the Royal Irish Academy in 1846.