white noise

white noise (uncountable)

2. (physics) A random signal (or process) with a flat power spectral density; a signal with a power spectral density that has equal power in any band, at any centre frequency, having a given bandwidth.
   • 2005, John G. Holden, Gauging the Fractal Dimension of Response Times from Cognitive Tasks‎^[1]:

     Conventional statistical analyses presuppose that intrinsic variability is white noise. White noise yields a jagged and irregular line with a fractal dimension of 1.5, because successive observations are statistically independent of each other.

3. (nontechnically) Any nondescript noise used for background or to mask or drown out other noise.
4. (by extension) Speech that goes ignored or uncomprehended.
   • 2017, C. R. Robertson, Elements of Fae, page 137:

     The rest was white noise; I was sick of listening to who I was supposed to be.

• pink noise, red noise, blue noise, violet noise, grey noise
• prewhiten

•   white noise on Wikipedia.Wikipedia