I've always like gizmo, gadget and dojigger myself, though the last has fallen into disuse. When speaking of the A-bomb, it's inventors called it "the gadget."
Gizmo only dates back to 1942, and first crops up in U.S. Marine and Navy usage at that time-it's of unknown origin (though it might be from one of Shakespeare's first drafts of Titus Andronicus,:
"She is a woman, therefore may be woo'd;
She is a woman, therefore may be won;
She is Lavinia, therefore must be loved.
What, man! more water glideth by the gizmo
Than wots the gizmoder of; and easy it is
Of a cut loaf to steal a shive"
Of course, "mill," (a kind of machine that existed before the theater or papier mache) scans better, as does "miller.":lfao:
Doohickey, of course, first enters the U.S. lexicon around 1914, a combination of doodad, and, oddly enough, dingbat, which was first used around 1840 for an alcoholic beverage whose recipe has been lost to time, but later came to mean many other things.....
Speaking of slang, machine is the only word in the English language used as a euphemism for both male and female genitalia......