whatchamacallit
what-cha-ma-cal-lit
noun
A placeholder for an object or person whose name one cannot recall.
"Could you pass me that whatchamacallit from the shelf?"
Thesaurus
Synonyms: thingumajig, gizmo, whatsis, thingummy, widget, dojigger, whatchamacallum, thingamabob, doodad, gubbins, doohickey, thingumabob