Phase

• The phase of a waveform is the position of any peak or trough compared to the same feature on a second waveform.
• A phase of matter is a physically distinctive form of a substance, such as the solid, liquid, and gaseous phases of ordinary matter.
• The Lunar phase refers to the appearance of the Moon as viewed from the Earth.
• The compositional technique of phase discovered by composer Steve Reich is while the same part is played on two instruments, one instrument keeps playing in steady tempo, while the other gradually moves ahead until it becomes back in phase (the rhythmic equivalent of cycling through the phase of two waveforms as above).