device (n.) Look up device at Dictionary.com
c. 1300, "intent, desire; an expressed intent or desire; a plan or design; a literary composition," from Old French devis "division, separation; disposition, wish, desire; coat of arms, emblem; a bequest in a will, act of bequeathing," from deviser "arrange, plan, contrive," literally "dispose in portions," from Vulgar Latin *divisare, frequentative of Latin dividere "to divide" (see divide (v.)).

The oldest sense is "method by which something is divided," which arose in Old French and led to the range of modern meanings. In English, from c. 1400 as "artistic design, work of art; ornament;" also "mechanical device," such as a large crossbow fitted with a crank. Also from late 14c. as "a disguise; a fashion in dress; a scheme, stratagem, an intrigue; boundary, division."