"whatchamacallits" in the noun sense
1. doodad, doohickey, doojigger, gimmick, gizmo, gismo, gubbins, thingamabob, thingumabob, thingmabob, thingamajig, thingumajig, thingmajig, thingummy, whatchamacallit, whatchamacallum, whatsis, widget
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® (An amazing lexical database of English)
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