stovepipe

noun

1. Sheet-metal tubing used as a chimney for a stove or furnace.

   “On the Visby-Västerhejde Railway there is a steam car. [...] The upperworks consist of a short clerestory coach body with end platforms and the engine chimney protruding from the roof like a stovepipe.”

   “Glass windows replaced the old tiny windows of selenite (crystallized gypsum), and stovepipe replaced adobe chimneys.”

2. A channel for information which is compartmentalized in such a manner that some parties who might be interested in its use or able to make use of it are restricted from accessing it.
3. A stovepipe hat.

   “I'm sure the Brunel-designed stone-built structure would have had a hatstand for his trademark stovepipe. I can picture him rocking up there of a morning and lobbing it nonchalantly onto the hatstand.”

4. A type of malfunction affecting breechloading firearms, where a spent cartridge casing fails to eject completely, instead becoming stuck in the firearm's ejection port, usually oriented vertically or nearly so.
5. (slang)A trench mortar such as the Stokes mortar.

verb

1. (idiomatic, transitive)To collect or store (information) in a compartmentalized manner, so that some parties who might be interested in its use or able to make use of it are restricted from accessing it.
2. (intransitive)Of a cartridge case, to become wedged vertically in the ejection port of a breechloading firearm, rather than ejecting completely from the weapon.