noun, feminine/dam.ʒan/plural: dames-jeannes
demijohn (bottle)
“Les trois autres s'occupaient à décoiffer une énorme dame-jeanne de vin de Collioure; c'étaient les laquais de ces messieurs.” — The three others were busy uncorking an enormous demijohn of Collioure wine; they were these gentlemen's lackeys.
Literally, “Lady Jane”; the name is an alteration of Jeanne.