night watch

Short definition from Wiktionary

Noun

1. 1
   A watch kept on some premises, or on a town, by guards during the night.
2. 2
   One or more of the guards on such a watch.
3. 3
   One of the watches kept on a marine vessel.
4. 4
   The sailors standing such a watch.
5. 5
   Alternative form of night watch.