The term you are looking for is "slope." The slope of a line is defined as the ratio of the change in the dependent values (outputs) to the change in the independent values (inputs) between two points on the line. It is often represented mathematically as:
\[ \text{slope} = \frac{\Delta y}{\Delta x} \]
where \( \Delta y \) is the change in the dependent variable (usually represented as \( y \)) and \( \Delta x \) is the change in the independent variable (usually represented as \( x \)).