Augean stables vs plural form

Augean stables and plural form both are nouns.

Word	Noun	Adjective	Verb	Adverb
Augean stables	Yes	No	No	No
plural form	Yes	No	No	No

Augean stables (noun)	plural form (noun)
(Greek mythology) the extremely dirty stables that were finally cleaned by Hercules who diverted two rivers through them	the form of a word that is used to denote more than one