early 13c., devisen, "to form, fashion;" c. 1300, "to plan, contrive, think or study out, elaborate in the mind," from Old French deviser "dispose in portions, arrange, plan, contrive" (in Modern French, "to chat, gossip"), from Vulgar Latin *divisare, frequentative of Latin dividere "to divide" (see divide (v.)).
Sense of "give, assign, or transmit by will" is from late 14c. in English, from Old French, via the notion of "to arrange a division." As a noun, "act of bequeathing by will" (1540s), also "a will or testament." Compare device. Related: Devised; devising.