Meaning : Something unspecified whose name is either forgotten or not known.
Example :
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.
Synonyms : doodad, doohickey, doojigger, gimmick, gismo, gubbins, thingamabob, thingamajig, thingmabob, thingmajig, thingumabob, thingumajig, thingummy, whatchamacallit, whatchamacallum, whatsis, widget
Meaning : A device or control that is very useful for a particular job.
Synonyms : appliance, contraption, contrivance, convenience, gadget, gismo, widget