Shot noise is a common term in physics and telecommunications, describing the random variation in the number of electrons passing through a conductor or semiconductor in a given time. Synonyms for shot noise include impulse noise, quantum noise, or photon noise. Impulse noise refers to irregular disturbances that occur in electrical signals, while quantum noise pertains to the unpredictability of subatomic particles in transit. Photon noise is specific to light and is caused by the randomness in the rate at which photons reach a sensor or photodetector. Other related terms include flicker noise, thermal noise, and white noise, all of which refer to sources of noise in signal processing.