plancher noun 3verb 1forms 3 noun3 •A floor made of wood. •A plank.Elm; [used] some for planchers — 1627 •The underside of a cornice; a soffit. verb1 •(no longer used) To form using planks.your stable be well paved with rounde stone, wel planchered and kept clean — 1586 formsplanchered · planchering · planchers