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"

doodad (Noun)

A thing (used in a vague way to refer to something whose name one cannot recall); especially an unspecified gadget, device, or part.