The term CHIMNEY CHANNEL refers to the passage through which smoke and other byproducts of combustion travel when a fire is lit. The crossword solutions for this term are FLUE (4 letters), SOOT (4 letters), and SWEEP (5 letters). A FLUE is an opening in a chimney that allows smoke and other gases to escape. SOOT is a black powdery substance that is created when fuel is burned incompletely. A SWEEP is a person who cleans out chimneys, removing SOOT and other debris.