tour vs duty period

tour and duty period both are nouns.

Word	Noun	Adjective	Verb	Adverb
tour	Yes	No	Yes	No
duty period	Yes	No	No	No

As nouns, duty period is a hypernym of tour; that is, duty period is a word with a broader meaning than tour:

tour: a time period for working (after which you will be relieved by someone else)
duty period: the time period during which you are at work

Other hypernyms of tour include shift, work shift.

tour (noun)	duty period (noun)
a journey or route all the way around a particular place or area	the time period during which you are at work
a time period for working (after which you will be relieved by someone else)
a period of time spent in military service

tour (verb)	duty period (verb)
make a tour of a certain place