The stage that a particle in vibration has reached in its CYCLE. Particles are in phase when they are at the same stage in the cycle at the same time, and out of phase when they are at opposite stages. Phase is measured by the angle of rotation, in degrees or radians.
(Greek: akouein = to hear) Commonly, the study of SOUND and its behaviour in various media and environments, including the effects of ABSORPTION, DIFFRACTION, INTERFERENCE, REFLECTION, and REFRACTION.
Any VIBRATION in the air or other medium, some types of which are able to cause a sensation of hearing.
If a sound is a complex of many TONEs of various FREQUENCY, AMPLITUDE and PHASE, repeating together in a basic CYCLE of definite frequency, the fundamental is the lowest frequency of this complex and corresponds to the unique PITCH heard in such a COMPLEX TONE.