Culture change that is initiated by

Culture change that is initiated by the conjunction of two or more autonomous
cultural systems. Acculturative change may be the consequence of direct cultural
transmission; it may be derived from non-cultural causes, such as ecological or
demographic modification induced by an impinging culture; it may be delayed, as
with internal adjustments following upon the acceptance of alien traits or patterns; or
it may be a reactive adaptation of traditional modes of life (Social Science Research
Council, 1954, p. 974)