While aliasing is the jagged edges on curves and diagonal lines in a bitmap image, anti-aliasing is the process of smoothing out those jagged edges.
Enlarging a bitmap image accentuates the effect and appearance of aliasing. Anti-aliasing adds additional pixels to make the edges of graphics and text appear less jagged. Font smoothing software provides anti-aliasing for on-screen type. Graphics software programs have options for anti-aliasing text and graphics.