Meaning : A long narrow furrow cut either by a natural process (such as erosion) or by a tool (as e.g. a groove in a phonograph record).
Synonyms : channel
Meaning : A settled and monotonous routine that is hard to escape.
Example :
They fell into a conversational rut.
Synonyms : rut
Meaning : (anatomy) any furrow or channel on a bodily structure or part.
Synonyms : vallecula