Gizmo
WordNet
noun
(1) A device or control that is very useful for a particular job
(2) 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"
WiktionaryText
Noun
- A nonsensical placeholder name for something that one does not know the proper term for; gadget; whatchamacallit; thingamajig; jobbyjobber.