rut [ rʌt ] noun
1. ) count usually singular a situation that is boring and difficult to change:
be (stuck) in a rut: If you're in a rut, change jobs.
2. ) count a deep narrow mark in the ground made by a wheel:
I had to walk in frozen ruts in the snow.
3. ) uncount the time of the year when some male animals are sexually active:
in rut: the sound of stags in rut

Usage of the words and phrases in modern English. 2013.

, / (of the sea)