[n] a journey or route all the way around a particular place or area; "they took an extended tour of Europe"; "we took a quick circuit of the park"; "a ten-day coach circuit of the island"
[n] a time for working (after which you will be relieved by someone else); "it's my go"; "a spell of work"
[n] a period of time spent in military service
[v] make a tour of a certain place