1rare Excessive regard or preference for what is internal or spiritual, often to the exclusion or neglect of external or practical considerations. Compare "externalism".
2Any of various theories which assert that certain relations are internal or that certain apparently disparate things are internally or intrinsically related. Also: any of various theories according to which certain practices or ways of life can only be understood or legitimately assessed on the basis of their own intrinsic characteristics rather than on the basis of external factors.
3In epistemology: any theory according to which all the factors which justify a person's belief or knowledge must be cognitively accessible to that person's conscious mind.
Mid 19th century; earliest use found in Present. From internal + -ism.