The Cartesian coordinate system is a two-dimensional grid used to locate points in space using pairs of numbers. Each point is defined by an x-coordinate and a y-coordinate, which represent its horizontal and vertical positions, respectively. The grid is divided into four quadrants, with the origin at the center, where both coordinates are zero. In this system, the x-axis runs horizontally, while the y-axis runs vertically. Points are plotted by moving along the x-axis first, followed by the y-axis. This method allows for precise representation of geometric shapes and is widely used in mathematics, physics, and engineering.