Backpropagation is an algorithm that updates the weights of a neural network based on the measured error at the output layer by layer up to the input.

ISO/IEC TR 29119-11:2020 method used in artificial neural networks to determine the weights to be used on the network connections based on the computed error at the output of the network

Note 1 to entry: It is used to train deep neural networks (3.1.27).