/ ˈdjuːəlɪzəm; NAmE ˈduː-/ noun [ U ]
1.
( philosophy ) the theory that there are two opposite principles in everything, for example good and evil
2.
( formal ) the state of having two parts
► dual·ist , dual·ist·ic adjective
► dual·ist noun
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WORD ORIGIN
late 18th cent.: from dual , on the pattern of French dualisme .