wedding night vs night

wedding night and night both are nouns.

Word	Noun	Adjective	Verb	Adverb
wedding night	Yes	No	No	No
night	Yes	No	No	No

As nouns, night is a hypernym of wedding night; that is, night is a word with a broader meaning than wedding night:

wedding night: the night after the wedding when bride and groom sleep together
night: the time after sunset and before sunrise while it is dark outside

Other hypernyms of wedding night include dark, nighttime.

wedding night (noun)	night (noun)
the night after the wedding when bride and groom sleep together	darkness
	the time after sunset and before sunrise while it is dark outside
	a period of ignorance or backwardness or gloom
	the dark part of the diurnal cycle considered a time unit
	the time between sunset and midnight
	the period spent sleeping
	a shortening of nightfall