Synaptic noise refers to the constant bombardment of synaptic activity in neurons. This occurs in the background of a cell when potentials are produced without the nerve stimulation of an action potential, and are due to the inherently random nature of synapses.

<communications> 1. Spurious characters due to electrical noise in a communications link, especially an EIA-232 serial connection. Line noise may be induced by poor connections, interference or crosstalk from other circuits, electrical storms, cosmic rays, or (notionally) birds crapping on the phone wires. 2. Any chunk of data in a file or elsewhere that looks like the results of electrical line noise. 3. Text that is theoretically a readable text or program source but employs syntax so bizarre that it looks like line noise. Yes, there are languages this ugly. The canonical example is TECO, whose input syntax is often said to be indistinguishable from line noise. Other non-WYSIWYG editors, such as Multics "qed" and Unix "ed", in the hands of a real hacker, also qualify easily, as do deliberately obfuscated languages such as INTERCAL. [Jargon File] (1994-12-22)

In science, Brownian noise, also known as Brown noise or red noise, is the type of signal noise produced by Brownian motion, hence its alternative name of random walk noise. The term "Brown noise" does not come from the color, but after Robert Brown, who documented the erratic motion for multiple types of inanimate particles in water.