Communication noise refers to parameters or factors that negatively influence or affects effective communication. And because of this interference, the process of sending, receiving and understanding a message effectively gets interrupted at some point.

Communication noise can affect the perception of a person while decoding a message. Thus, noise can significantly influence the communication process as a whole.

To say in other words, communication is the process of sending or transmitting an information from the source to the receiver. And communication noise is any disruption in the process of transmitting or receiving or understanding that message.

Most common forms of communication noise include:

1. Physical/Environmental noise: any external or environmental stimulus, usually defined as 'noise pollution' (e.g. sound caused by transport)
2. Psychological noise: such as preconceived notions (e.g. stereotypes, biases, assumptions)
3. Physiological noise: distractions or disturbances created by physiological processes (e.g. biological or other physical issues like hearing problem, or loss of vision)
4. Semantic noise: the gap created between the Source and Receiver because of having different meaning systems

Each of these noises interferes with the communication process in different ways.

References

European Commission. The Green Paper on Future Noise Policy.
Rothwell, Dan J (2004). In the Company of Others: An Introduction to Communication. New York: McGraw Hill.