The phenomenon that waves of electromagnetic radiation (light) can act as particles and that particles of matter can act as waves. See also: Heisenberg Uncertainty Principle, electromagnetic radiation, quantum, De Broglie, Louis, Advanced Topics

The principle that all objects in motion are simultaneously particles and waves. Most objects have a wavelength that is too small to be detected. Very light objects, such as photons and electrons, can have wave-lengths large enough to give these objects some of the properties of waves.

basic feature of quantum mechanics that objects manifest both wavelike and particle-like properties.