Y-intercept

Graph $y=f(x)$ with the $x$-axis as the horizontal axis and the $y$-axis as the vertical axis. The $y$-intercept of $f(x)$ is indicated by the red dot at $(x=0,y=1)$.

Graph of a function depicting its Y-intercept on the Y-axis, with coordinates $(0,b)$

In analytic geometry, using the common convention that the horizontal axis represents a variable $x$ and the vertical axis represents a variable $y$, a $y$-intercept or vertical intercept is a point where the graph of a function or relation intersects the $y$-axis of the coordinate system. As such, these points satisfy $x=0$.