variety of sound, usually meaning any unwanted sound
Noise is another word for sound. It usually means it is not wanted. Noise is perceived by our ears. They can be damaged by noise. Noise is created through any object, which produces vibration unnecessarily.
Noise can also mean data (information) that typically does not have a meaning, like white noise. Loudspeaker measurements can use white noise for measuring loudspeakers frequency response.
Noise can also refer to some math that makes random numbers. Click here to learn about it.
In electronics, heat produces noise in resistors. Depending on the type of resistor, the amount of noise may differ. Most audio devices are designed not to produce noise.