Etymology

Noun

1. 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 hydro-carbon based fuels); a flue.
   • 1883: Robert Louis Stevenson, Treasure Island

     Our chimney was a square hole in the roof: it was but a little part of the smoke that found its way out, and the rest eddied about the house, and kept us coughing and piping the eye.

2. The glass flue surrounding the flame of an oil lamp.
3. The smokestack of a steam locomotive.
4. A narrow cleft in a rock face.