white sale vs sales event

white sale and sales event both are nouns.

Word	Noun	Adjective	Verb	Adverb
white sale	Yes	No	No	No
sales event	Yes	No	No	No

As nouns, sales event is a hypernym of white sale; that is, sales event is a word with a broader meaning than white sale:

white sale: a sale of household linens
sales event: an occasion (usually brief) for buying at specially reduced prices

Other hypernyms of white sale include cut-rate sale, sale.

white sale (noun)	sales event (noun)
a sale of household linens	an occasion (usually brief) for buying at specially reduced prices