THINGAMABOB

doodad, doohickey, doojigger, gimmick, gizmo, gismo, gubbins, thingamabob, thingumabob, thingmabob, thingamajig, thingumajig, thingmajig, thingummy, whatchamacallit, whatchamacallum, whatsis, widget

(noun) something unspecified whose name is either forgotten or not known; “she eased the ball-shaped doodad back into its socket”; “there may be some great new gizmo around the corner that you will want to use”

Source: WordNet® 3.1

Noun

thingamabob (plural thingamabobs)

(slang) A thing or person whose actual name is unknown or forgotten.

Synonyms

• See also thingy

• See also whatsaname

Source: Wiktionary