Pink noise

1. A noise signal whose spectrum level decreases at a 3-dB-per-octave rate. This gives the noise equal energy per octave.
2. An audio signal with equal energy at all octaves. Used to "tune" a sound reinforcement system so it provides a natural, musical sound. Source: Church Audio & Acoustics Glossary
3. Noise for which the spectrum density varies as the inverse of frequency. Source: Glossary of Terms in Noise Control Engineering
4. In acoustics, noise in which there is equal power per octave. Source: http://www.its.bldrdoc.gov/projects/devglossary/_pink_noise.html
5. Noise with a continuous frequency spectrum and with equal power per constant percentage bandwidth. For example, equal power is any one-third octave band. Source: http://www.owenscorning.com/around/sound/glossary.asp