prepared with finely sliced onions; esp., designating potatoes prepared with fried onions
Origin of lyonnaiseFr, feminine of Lyonnais, of Lyon
Cooked with onions: lyonnaise potatoes; potatoes lyonnaise.
Origin of lyonnaiseFrom French (à la) Lyonnaise (in the manner) of Lyon from Lyon
Unlike most English adjectives, lyonnaise typically follows the noun that it describes.
From French lyonnaise (“in the manner of Lyons").