WordReference Random House Learner's Dictionary of American English © 2015
- Informal Termsa gadget or other thing for which the speaker does not know or has forgotten the name.
thingum or thingummy + jig1, metrically patterned like gobbledygook, rigamarole;
thingum perh. origin, originally from the gradational compound thingum-thangum (based on thing1) with the same terminal syllable as in crinkum-crankum, harum-scarum, trinkum-trankum, the ultimately origin, originally of which is unclear