week vs period

week and period both are nouns.

Word	Noun	Adjective	Verb	Adverb
week	Yes	No	No	No
period	Yes	No	No	No

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

Other hypernyms of week include period of time, time period.

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

week: a period of seven consecutive days (usually reckoned to be from Sunday to Saturday, or from Monday to Sunday)
period: an amount of time

Other hypernyms of week include period of time, time period.

week (noun)	period (noun)
any period of seven consecutive days	a punctuation mark (.) placed at the end of a declarative sentence to indicate a full stop or after abbreviations
hours or days of work in a calendar week	the monthly discharge of blood from the uterus of nonpregnant women from puberty to menopause
a period of seven consecutive days (usually reckoned to be from Sunday to Saturday, or from Monday to Sunday)	an amount of time
	the interval taken to complete one cycle of a regularly repeating phenomenon
	a unit of geological time during which a system of rocks formed
	the end or completion of something
	(ice hockey) one of three divisions into which play is divided in hockey games