| A | B |
| regular reflection | The bouncing back of light from a smooth, even surface. |
| diffuse reflection | The bouncing back of light from an uneven surface. |
| plane mirror | A mirror with a perfectly flat face. |
| concave mirror | A mirror with a surface that curves inward. |
| convex mirror | A mirror with a surface that curves outward. |
| focal point | Location at which light rays reflected from a mirror meet. |
| index of refraction | Comparison of speed of light in air with the speed of light in a certain material. |
| lens | Transparent material the refracts light. |
| convex lens | A lens that is thicker in the middle than at the edges. |
| concave lens | Lens that is thicker at the ends than in the middle. |