week vs Passion Week

week and Passion Week both are nouns.

Word	Noun	Adjective	Verb	Adverb
week	Yes	No	No	No
Passion Week	Yes	No	No	No

As nouns, Passion Week is a hyponym of week; that is, Passion Week is a word with a more specific, narrower meaning than week:

Other hyponyms of week include week from Monday, rag, rag week, Holy Week, shibah, shiva, shivah.

week (noun)	Passion Week (noun)
any period of seven consecutive days	the week before Easter
hours or days of work in a calendar week
a period of seven consecutive days (usually reckoned to be from Sunday to Saturday, or from Monday to Sunday)