The Collaborative International Dictionary
Bolthead \Bolt"head`\, n.
(Chem.) A long, straight-necked, glass vessel for chemical distillations; -- called also a matrass or receiver.
The head of a bolt.
Wiktionary
n. 1 (context chemistry English) A round-bottomed flask with a long neck (used especially for distillation) 2 The head of a bolt.
Usage examples of "bolthead".
Mop-up troops are now in the ~ Jan sidled forward-and his shirt caught on a protruding bolthead, held an instant, then ripped free.
He threw the switch and the red light above the steel door, studded with boltheads and massive rivets, turned to green.
The table was gone from the booth, and there were only cracked plaster and boltheads to show where it had once been moored to the wall.
Give the new beings what is useful - as it might be iron for forging boltheads for the hunt - but a piece of technology at a time, maybe once in a century, so they can grow into the use, not the misuse-" Caitlin laid a palm over Brodersen's mouth.
My muscles ached, I was dented all over from sleeping on boltheads, and my skin was lightly oiled with the dirt and grit of two nations.