(noun)
a groove, track, or channel in a surface that is caused by the wearing down of the surface by the repeated or habitual passage of something on the same path, especially by the wheels of a vehicle;
e.g. The carriage wheel ran in the rut in the road, which kept it steady.
(noun)
a fixed habit or routine, a pattern of behavior that has become monotonous and often unproductive, but that is difficult to change or escape from;
e.g. He feels that he has become stuck in a rut and he is bored of doing the work that he does every day.
(noun)
the season during the year when large animals such as deer show an urge to breed, particularly characterized by the males being aggressive in order to gain access to the females;
e.g. They thought that many of the deer might be in rut and therefore more aggressive than usual.
(verb)
to engage in the annual period of increased breeding activity, used to describe the behavior of animals such as deer;
e.g. The deer have begun to rut early this year.
(verb)
to make a furrow or groove in something;
e.g. The carpenter used a special tool to rut the wood so the pieces would fit together.