late 15c., machinacion, "a plotting, an intrigue," from Old French machinacion "plot, conspiracy, scheming, intrigue" and directly from Latin machinationem (nominative machinatio) "device, contrivance, machination," noun of action from past-participle stem of machinari "to contrive skillfully, to design; to scheme, to plot," from machina "machine, engine; device trick" (see machine (n.)). Related: Machinations.

"instrument used to measure the intensity of light," 1778, from photo- "light" + -meter "device for measuring." Related: Photometric; photometry (1760).

1891 (n.) "a contraceptive device or drug;" 1915 (adj.) "pertaining to contraception; preventing conception," from stem of contraception + -ive.

by 1940, "device that gives electrical pulses," agent noun from pulse (v.).

"device placed behind a door to prevent it from being opened too widely," 1859, from door + stop (n.).

a slighting word for "a device, a contrivance," 1825, western England dialect, origin obscure, perhaps from con(trive) + trap, or deception.

"computer operating system using a disk storage device," 1967, acronym of disk operating system.