| Term | Definition |
| Compressional Wave | Mechanical wave that causes particles in matter to move back and forth along the direction the wave travels. |
| Diffraction | Bending of waves around an object. |
| Electromagnetic Wave | Waves that can travel matter or empty space, includes radio waves, infrared waves, visible light waves, ultraviolet waves, X rays, and gamma rays. |
| Electromagnetic Spectrum | Complete range of electromagnetic wave frequencies and wavelengths. |
| Frequency | Number of wavelengths that pass a give point in one second, measured in hertz. |
| Infrared Waves | Electromagnetic waves with wavelengths between about one thousandth of a meter and 700 billionths o a meter. |
| Intensity | Amount of energy a wave carries past a certain area each second. |
| Law Of Reflection | States that the angle the incoming wave makes with the normal to the reflecting surface equals the angle the reflected wave makes with the surface. |
| Pitch | Human perception of the frequency of sound. |
| Refraction | Change direction of a wave when it changes speed as it travels from one material into another. |
| Reverberation | Repeated echoes of sound waves. |
| Transverse Waves | Mechanical wave that causes particles in matter to move at right angles to the direction the wave travels. |
| Ultraviolet Waves | Electromagnetic waves with wavelengths between about 400 billionths and 10 billionths of meter. |
| Wave | Disturbance that moves through matter and space and carries energy. |
| Wavelength | Distance between one point on a wave and the nearest point moving with the same speed and direction |
