The word "devise" entered English in the 13th century from Anglo-French deviser, which came from Old French deviser (to divide, distribute, arrange, discuss, plan). The Old French verb derived from Vulgar Latin *divisare, a frequentative form of Latin dividere (to divide, to separate). The Latin verb combines dis- (apart) with a root that may be related to vidua (bereft, widowed — one who has been separated from a spouse).
The semantic development from "divide" to "plan" is more logical than it might initially appear. Dividing involves analysis — breaking something into parts, examining the components, and arranging them purposefully. Planning involves the same cognitive operations: taking a complex objective, breaking it into steps, and arranging those steps in a productive sequence. The Old French verb deviser captured both: to devise was to divide and arrange, whether the object was physical property, a narrative, or a plan of action.
The legal sense of "devise" — to bequeath real property by will — preserves the oldest meaning most faithfully. In property law, a "devise" is specifically the transfer of real estate (land and buildings) through a will, as distinguished from a "bequest" (personal property) or a "legacy" (money). The person making the devise is the "devisor," and the recipient is the "devisee." This legal vocabulary maintains the original sense
The related word "device" took a different but parallel path. Originally meaning a plan, a design, or a heraldic emblem, "device" gradually narrowed to mean a mechanical contrivance — something that has been devised, planned, and constructed. The "device" on a coat of arms (a heraldic design) and the "device" in your pocket (a smartphone) share the same root: both are products of careful planning and arrangement.
Old French deviser also meant "to discuss" or "to converse" — a usage that survives in the phrase "to devise" in some Romance languages. The connection to division is clear: discussion involves dividing a topic into parts and examining each in turn. French devis (an estimate, a plan) and deviser (to chat) preserve these distinct semantic branches.
The word "dividend" — something to be divided — comes from the same Latin root, as does "individual" (unable to be divided further). The mathematical operation of division, the legal division of an estate, and the intellectual division of a problem into solvable components all radiate from the single Latin concept of separating a whole into parts.