brown onion sauce vs Lyonnaise sauce

brown onion sauce and Lyonnaise sauce both are nouns.

Word	Noun	Adjective	Verb	Adverb
brown onion sauce	Yes	No	No	No
Lyonnaise sauce	Yes	No	No	No

As nouns, brown onion sauce and Lyonnaise sauce are synonyms defined as:

brown onion sauce and Lyonnaise sauce: brown sauce with sauteed chopped onions and parsley and dry white wine or vinegar

brown onion sauce (noun)	Lyonnaise sauce (noun)
brown sauce with sauteed chopped onions and parsley and dry white wine or vinegar	brown sauce with sauteed chopped onions and parsley and dry white wine or vinegar