| Term | Definition |
| reflection | when waves bounce back into their original medium |
| partial reflection | occurs when some light is reflected, while other parts of the light are transmitted |
| Law of Reflection | the angle of incidence = the angle of reflection |
| virtual image | an image that appears to be in a location where light does not really reach |
| concave mirror | concentrates an image to point (focus) in front of the mirror |
| convex mirror | curve outwards and they make light diverge |
| reverberations | when too many sound reflections cause the sound to be garbled |
| acoustics | the study of sound |
| refraction | when a wave crosses a boundry between different media at an angle, it bends because it slows or speeds up |
| normal | line perpendicular to the surface |
| diffuse reflection | reflection of light from a rough surface |
| wave fronts | lines that represent the positions of different crests |
| plane mirror | mirror in which object size = image distance |
| echo | reflected sound |
| ray | perpendicular to the wave front in a wave |
| mirage | caused by the refraction of light in Earth's atmosphere |
| critical angle | angle of incidence that results in the light being refracted at an angle of 90 degrees with respect to the normal |
| optical fibers | pipe light from one place to another |