Gadget
late 19th century (originally in nautical use): probably from French gâchette ‘lock mechanism’ or from the French dialect word gagée ‘tool’.
wiktionary
Unknown. First used in print by Robert Brown in 1886 (see quote in definition section). Might come from French gâchette or gagée, or from the French family name Gaget, an industrialist who produced promotional gadgets in collaboration with the project to build the statue of Liberty.
etymonline
gadget (n.)
1886, gadjet (but said by OED corespondents to date from 1850s), sailors' slang word for any small mechanical thing or part of a ship for which they lacked, or forgot, a name; perhaps from French gâchette "catch-piece of a mechanism" (15c.), diminutive of gâche "staple of a lock." OED says derivation from gauge is "improbable."
