What does "axis" refer to in a coordinate system?

In a coordinate system, "axis" refers to one of the two lines that divide the plane into quadrants, typically the x-axis and y-axis in a two-dimensional Cartesian coordinate system. The x-axis is the horizontal line, while the y-axis is the vertical line. These axes serve as reference lines from which the coordinates of any point in the plane are measured. For example, any point can be expressed in terms of its distances from these two axes, helping to establish its location in the plane. This foundational concept is crucial for graphing functions, analyzing geometric shapes, and understanding the relationships between different points in a coordinate system.

The other options describe different concepts that are not directly related to the definition of an axis. For example, a shape defined by two intersecting lines pertains more to geometric figures rather than coordinate frameworks, while the angle between two lines relates to angular measurement, and a measurement of distance from the origin describes the concept of radius or coordinates rather than the axes themselves.