A systematic plan of action: "Did you ever carry out your scheme of writing a series of sonnets embodying all the great epochs of art?\u201d ( Edith Wharton). A secret or devious plan; a plot. See Synonyms at plan. An orderly combination of related parts: an irrigation scheme with dams, reservoirs, and channels. A chart, diagram, or outline of a system or object. To plot: scheming their revenge. To contrive a plan or scheme for. To make plans, especially secret or devious ones.