The definition of a neural network, as provided by the inventor of one of the first neurocomputers, Dr. Robert Hecht-Nielson, in Neural Network Primer—Part I, is as follows:
"A computing system made up of a number of simple, highly interconnected processing elements, which process information by their dynamic state response to external inputs."
In practice, we can think of artificial neural networks as a computational model that is based on how the brain is believed to work. Hence, the mathematical model is inspired by biological neurons.