a vertical flue that provides a path through which smoke from a fire is carried away through the wall or roof of a building
"The old brick chimney drew the smoke from the hearth up and out through the roof."
a glass flue surrounding the wick of an oil lamp
"The old oil lamp had a small chimney around its wick to keep the flame steady and bright."
A vertical tube or hollow column used to emit environmentally polluting gaseous and solid matter (including but not limited to by-products of burning carbon or hydrocarbon based fuels); a flue.
"The factory's tall chimney released thick black smoke into the sky, signaling another day of heavy pollution from burning coal."
In plain English: A chimney is an open tube built into a building that lets smoke and hot air escape from a fireplace to the outside.
"We need to clean out the chimney before winter arrives so smoke doesn't fill the house."
Usage: The primary noun sense refers specifically to an artificial structure for venting smoke or gases from buildings, whereas climbing through a natural rock opening is described as "chimneying." Do not use the verb form when referring to exiting a building via a fire escape; instead, specify that action directly.
To negotiate a chimney (narrow vertical cave passage) by pushing against the sides with back, feet, hands, etc.
"The climber had to carefully climb down the narrow chimney in the canyon wall using only his hands and feet."
In plain English: To chimney is to move upward quickly through an opening, usually by jumping over something low.
"The old fireplace began to chimney smoke when we lit the fire for winter."
The word chimney entered English via Middle English and Old French as a borrowing from the Late Latin camīnāta, which originally meant "a furnace." Its roots trace back to Ancient Greek κάμῑνος, where it also referred to a furnace or oven.