What is y axis?

The y-axis is the vertical axis on a Cartesian coordinate system, used to plot numerical values. It is the second axis after the x-axis and is perpendicular to it. The values on the y-axis represent the dependent variable in a mathematical or scientific equation. The y-axis can also be referred to as the ordinate. The y-axis is typically labeled with a unit of measurement and a title that describes the data being plotted. The placement of the x and y-axes on a graph can vary depending on the context and the range of values being plotted.