A chimney or smokestack: a vertical pipe or funnel on a building, factory, or ship used to vent smoke and exhaust gases.
工場の煙突から黒い煙が上がっている。
Black smoke is rising from the factory's smokestack.
古い家は煙突の掃除が必要だ。
Old houses need chimney cleaning.
船の煙突から白い蒸気が吹き出しているのが見えた。
I saw white steam blowing out from the ship's funnel.
Slang: carrying a passenger without running the meter (i.e., taxi drivers taking fares without using the meter).
彼は若い頃、煙突で客を運んでいたと友達に話していた。
He told his friends that when he was young he used to carry passengers without using the meter.