A cellular automaton is Life-like if it meets the following criteria:

• The CA has two dimensions.
• The CA has two states (called OFF and ON).
• The neighborhood is the Moore neighborhood ; it consists of the eight adjacent cells to the one under consideration and (possibly) the cell itself.
• The new state of the cell in the next generation can be expressed as a function of the number of adjacent cells that are in the ON state and the cell's own state.

There is a notation used to describe these automata. It is written in the form S/B. S (for survival) is a list of all the numbers of states that cause an ON cell to remain ON. B (for birth) is a list of all the numbers of states that cause an OFF cell to turn on. If 0 is in the list, then blank regions of the universe will turn on in one generation.

As an example, the Seeds rule is described as /2. Thus every ON cell dies in every generation, since the survival list is empty. All OFF cells that had exactly two adjacent ON cells then turn ON.

This class of cellular automata is named for the Game of Life (23/3), the most famous cellular automaton. Many different terms are used to describe this class. It is common to refer to it as the "Life family" or to simply use phrases like "similar to Life".