dry rot vs fungus

dry rot and fungus both are nouns.

Word	Noun	Adjective	Verb	Adverb
dry rot	Yes	No	No	No
fungus	Yes	No	No	No

As nouns, fungus is a hypernym of dry rot; that is, fungus is a word with a broader meaning than dry rot:

dry rot: a fungus causing dry rot
fungus: an organism of the kingdom Fungi lacking chlorophyll and feeding on organic matter; ranging from unicellular or multicellular organisms to spore-bearing syncytia

dry rot (noun)	fungus (noun)
a fungus causing dry rot	an organism of the kingdom Fungi lacking chlorophyll and feeding on organic matter; ranging from unicellular or multicellular organisms to spore-bearing syncytia
a crumbling and drying of timber or bulbs or potatoes or fruit caused by a fungus