A computational model composed of a grid of stateful cells and a set of rules describing when to change a cell's state.

A cellular automaton (CA) is a discrete model of computation consisting of a finite-dimensional grid of stateful cells, a finite set of states, and a fixed function that relates the state of a cell at time $t$ to the state of a cell's neighborhood at time $(t-1)$.

Questions tagged with cellular-automata typically examine some property of CAs, specific CA rule sets, or the relationship of cellular automata to other models of computation.