1. The distance of a point from the vertical axis of a graph as measured parallel to the horizontal axis: "The abscissa was highlighted in red on the graph."

2. In mathematics, the horizontal coordinate or x-coordinate of a point in a two-dimensional system of Cartesian coordinates: "The abscissa is the distance from the vertical axis or y-axis measured along a line parallel to the horizontal axis or x-axis."

"In the statistics class, students were asked to explain the abscissa on the graph.'

"The various abscissas on the graph were highlighted in different colors."