What does "doohickey" mean?

A thing (used in a vague way to refer to something whose name one does not know or cannot recall)

What is a synonym for "doohickey"?

Common synonyms include: gizmo, thingamajig, widget, assembly, component, contraption.

/ˈduhɪki/ noun, slang

noun, slang ·Moderate ·College level

Noun

1
A thing (used in a vague way to refer to something whose name one does not know or cannot recall) slang
"What does this doohickey do?"
2
something unspecified whose name is either forgotten or not known wordnet

"Ah, crap. I dropped my doohickey into the sink."

First attested 1914, of uncertain origin, probably from doodad + hickey.