Lady Day vs quarter day

Lady Day and quarter day both are nouns.

Word	Noun	Adjective	Verb	Adverb
Lady Day	Yes	No	No	No
quarter day	Yes	No	No	No

As nouns, quarter day is a hypernym of Lady Day; that is, quarter day is a word with a broader meaning than Lady Day:

Lady Day: a festival commemorating the announcement of the Incarnation by the angel Gabriel to the Virgin Mary; a quarter day in England, Wales, and Ireland
quarter day: a Christian holy day; one of four specified days when certain payments are due

Lady Day (noun)	quarter day (noun)
a festival commemorating the announcement of the Incarnation by the angel Gabriel to the Virgin Mary; a quarter day in England, Wales, and Ireland	a Christian holy day; one of four specified days when certain payments are due