Definition of thingamajig in English:

thingamajig

(also thingumajig, thingamabob, thingumabob)

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’
    thingy
    and → thingummy

Origin

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

Pronunciation:

thingamajig

/ˈTHiNGəməˌjiɡ/