Reductionism: An attempt to explain some domain or field by showing that it can be derived from or redescribed in the language of some more basic domain or field. A physicalist, for example, may attempt a reductionistic account of the mind by showing that such entities as thoughts and perception can be reduced to physiological states of the brain. In science a successful reduction requires one to show how the laws of one domain can be derived from the laws of some more fundamental domain. Reductionism often is linked to an attitude that seeks to view the explained or "reduced" field or objects as unreal.1
1. C.Stephen Evans, Pocket Dictionary of Apologetics & Philosophy of Religion (Downers Grove, IL: InterVarsity Press, 2002), p. 100.