1. in general, the quality or condition of being parallel, being structurally similar, or having corresponding features.

2. in philosophy, the proposition that, although mind and body constitute separate realities, they function in parallel such that their responses seem holistic and the two realms seem to assert causal control over each other. See mind–body problem. See also occasionalism; preestablished harmony.

3. in anthropology, see cultural parallelism.