Patterns are those arrangements or systems of internal relationship which give to any culture its coherence or plan, and keep it from being a mere accumulation of random bits.
They are therefore of primary importance.〔Kroeber, Alfred L. Anthropology: Culture, Patterns, and Process. New York: Harcourt, Brace and World, 1948, p. 119〕

A second kind of pattern consists of a system or complex of cultural material that has proved its utility as a system and therefore tends to cohere and persist as a unit; it is modifiable only with difficulty as to its underlying plan. Any one such systemic pattern is limited primarily to one aspect of culture, such as subsistence, religion, or economics; but it is not limited areally, or to one particular culture; it can be diffused cross-culturally, from one people to another. . . . What distinguishes these systemic patterns of culture—or well-patterned systems, as they might also be called—is a specific interrelation of their component parts, a nexus that holds them together strongly, and tends to preserve the basic plan... As a result of the persistence of these systemic patterns, their significance becomes most evident on a historical view.
〔Kroeber, Alfred L. Anthropology: Culture, Patterns, and Process. New York: Harcourt, Brace and World, 1948, pp. 120 - 121.〕