Crests: A 'crest' is the point on a wave with the maximum value or upward displacement within a cycle
Troughs: A trough is the opposite of a crest, so the minimum or lowest point in a cycle
Period: Period is the duration of time it takes for a wave to complete one cycle of oscillation.
Frequency: Frequency refers to how many waves are made per time interval. This is usually described as how many waves are made per second, or as cycles per second.
Amplitude: Highest or lowest possible measurement of displacement of the wave from equilibrium.
Wavelength: The wavelength of a wave is the distance between any two adjacent corresponding locations on the wave train. This distance is usually measured in one of three ways: Crest to the next crest, trough to next trough, or from the start of a wave cycle to the next starting point.
Interference: The adding of the amplitude of two or more waves "combining" at a point in space
Medium: A medium is a substance or material that carries the wave. The wave medium is not the wave and it doesn't make the wave; it merely carries or transports the wave from its source to other locations. In the case of our slinky wave, the medium through that the wave travels is the slinky coils. In the case of a water wave in the ocean, the medium through which the wave travels is the ocean water. In the case of a sound wave moving from the church choir to the pews, the medium through which the sound wave travels is the air in the room.
Wave Front: The set of points in space reached by a wave or vibration at the same instant as the wave travels through a medium. Wave fronts generally form a continuous line or surface. The lines formed by crests of ripples on a pond, for example, correspond to curved wave fronts.
Ray: In physics, term denoting the straight line along which light or other types of waves propagates from its source. It generally refers to the line of propagation of waves but is also applied to streams of particles such as the electrons emitted from a cathode or particles emitted by substances exhibiting radioactivity. A ray is drawn perpendicular to the wave front.
Sine Wave: A typical method of representing a property of a wave is as a sine wave. When a sine wave is used to represent a wave, were only looking at a single property such a displacement, energy, or in the case of light electric or magnetic field strength.