stovepipe noun 5verb 3forms 3phrases 1 noun5 •Sheet-metal tubing used as a chimney for a stove or furnace.Glass windows replaced the old tiny windows of selenite (crystallized gypsum), and stovepipe replaced adobe chimneys. — 1994 •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. — 2021 •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. •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. •(slang) A trench mortar such as the Stokes mortar. verb3 •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. •Of a cartridge case, to become wedged vertically in the ejection port of a breechloading firearm, rather than ejecting completely from the weapon. •To improperly share classified information or share such information without sufficient context. formsstovepiped · stovepiping · stovepipes Phrases with stovepipe stovepipe hatA type of top hat worn mainly in the 19th century, made of silk or other materials and having a very tall, cylindrical, flat-topped crown.