In response to another answer, noise should definitely not be replaced with sound.
A tone generally refers to a single frequency. Sound is a general term, but would usually be used when you are talking about a single tone or collection of tones.
The distinction between sound and noise depends on your perspective: there is the signal you want and the signal you don't want. Sound would be the signal you want, and noise the signal you do not want.
Noise is often modeled as a random process, but this is not always true. When using analog electronics to monitor someone's heartbeat, the signal you want is the person's heartbeat. Noise manifests in the form of a 60 Hz sine-wave (sometimes harmonics as well), which will become present when viewing the person's heartbeat.