Differencing and Device

Subtracting previous from current values to obtain a stationary (detrended) time series: P stationary = Pt - Pt-1.

noun

• An instrumentality invented for a particular purpose.
  • usage: "the device is small enough to wear on your wrist"; "a device intended to conserve water"
• Something in an artistic work designed to achieve a particular effect.
• Any clever maneuver.
  • usage: "he would stoop to any device to win a point"; "it was a great sales gimmick"; "a cheap promotions gimmick for greedy businessmen"
  • synonyms: gimmick, twist
• Any ornamental pattern or design (as in embroidery. )
• An emblematic design (especially in heraldry. )
  • usage: "he was recognized by the device on his shield"

• (n.) Anything fancifully conceived.
• (n.) Opinion; decision.
• (n.) That which is devised or formed by design; a contrivance; an invention; a project; a scheme; often, a scheme to deceive; a stratagem; an artifice.
• (n.) Improperly, an heraldic bearing.
• (n.) An emblematic design, generally consisting of one or more figures with a motto, used apart from heraldic bearings to denote the historical situation, the ambition or the desire of the person adopting it. See Cognizance.
• (n.) A spectacle or show.
• (n.) Power of devising; invention; contrivance.