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late 13c., from Old French devis "division, separation, disposition, wish, desire; coat of arms, emblem; last will," from deviser "to divide, distribute" (see devise). Sense of "method by which something is divided" arose in French and led to modern meaning.
device de·vice (dĭ-vīs')
A contrivance or an invention serving a particular purpose, especially a machine used to perform one or more relatively simple tasks.