Definition of thingamajig in English:

thingamajig

(also thingumabob, thingumajig, thingamabob)

noun

informal
  • Used to refer to or address a person or thing whose name one has forgotten, does not know, or does not wish to mention.

    ‘one of those thingamajigs for keeping all the fireplace tools together’

Origin

Early 19th century: arbitrary extension of earlier thingum (from thing + a meaningless suffix). Thingumabob dates from the mid 18th century.

Pronunciation:

thingamajig

/ˈTHiNGəməˌjiɡ/