from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Informal An unnamed gadget or trinket.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A thing (used in a vague way to refer to something whose name one cannot recall)
from the GNU version of the Collaborative International Dictionary of English
- n. Any object, usually a tool or other device, whose name is forgotten, or not known.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. something unspecified whose name is either forgotten or not known
Perhaps doo(dad) + hickey.(American Heritage® Dictionary of the English Language, Fourth Edition)
First attested 1914, of uncertain origin, probably from doodad + hickey. (Wiktionary)