|Origin:||thingum 'thingamajig' (17-19 centuries), from thing|
thing‧a‧ma‧jig also thing‧a‧ma-bob, thing‧y [countable] spoken
used when you cannot remember or do not know the name of the thing you want to mention:
What do you call that thingamajig? You know - the circle with the line through it.
2 British English
used when you cannot remember or do not know the name of the person you want to mention:
Is thingy going?