After talking about various graphs, you might ask “What is a graph?”. It is a diagram that exhibits a relationship, often functional, between two sets o f numbers as a set of points having coordinates determined by the relationship. A pictorial device, such as a pie chart or bar graph, used to illustrate quantitative relationships. Two-dimensional drawing showing a relationship (usually between two set of numbers) by means of a line, curve, a series of bars, or other symbols. Typically, an independent variable is represented on the horizontal line (X- axis) and an dependent variable on the vertical line (Y-axis). The perpendicular axis intersect at a point called origin, and are calibrated in the units of the quantities represented. Though a graph usually has four quadrants representing the positive and negative values of the variables. A graph is a visual way to display information.

To make a graph, people often use a paper like this:

Now, you know what is a graph.