The x-intercept of a line is the x-coordinate of the point where the line crosses the x-axis. The y-intercept of a line is the y-coordinate of the point where the line crosses the y-axis. The y-intercept of an equation is also known as its initial value.

When talking about functions, the x-intercepts are the zeros of the function. Sometimes, only one coordinate of these points is referenced. For example, if the x-intercept lies at (a,0), it can be said that the x-intercept is at x=a. The same is true for the y-intercept. A relation can have several intercepts. A function can have multiple x-intercepts, but it can only have one y-intercept.