weather deck vs upper deck

weather deck and upper deck both are nouns.

Word	Noun	Adjective	Verb	Adverb
weather deck	Yes	No	No	No
upper deck	Yes	No	No	No

As nouns, upper deck is a hypernym of weather deck; that is, upper deck is a word with a broader meaning than weather deck:

weather deck: upper deck having no overhead protection from the weather, but sheltering the deck below
upper deck: a higher deck

weather deck (noun)	upper deck (noun)
upper deck having no overhead protection from the weather, but sheltering the deck below	a higher deck