A Moore machine can be defined as follows:

Compare with a Mealy machine, which maps transitions in the machine to outputs.

The name Moore machine comes from that of their promoter: E. F. Moore, a state machine pioneer, who wrote Gedanken-experiments on Sequential Machines, pp 129 – 153, Automata Studies, Annals of Mathematical Studies, no. 34, Princeton University Press, Princeton, N. J., 1956