Check the picture below.
the slope goes by several names
• average rate of change
• rate of change
• deltaY over deltaX
• Δy over Δx
• rise over run
• gradient
• constant of proportionality
however, is the same cat wearing different costumes.
well, by the definition of a derivative, the slope at the point is f'(a), and any tangent line going through it will also have the same exact slope, keeping in mind that a straight line has a constant slope.