In ch.5 we are told that "every search for [Henry Tilney] was equally unsuccessful, in morning lounges or evening assemblies; neither at the Upper nor Lower Rooms, at dressed or undressed balls, was he perceivable".

The footnote in my Norton Critical Edition says "dressed and undressed balls" were "those requiring formal attire or not", but I'm still puzzled about "morning lounges". Can anybody help me out? (And I'd love to know what JA and her contemporaries would have considered the difference between formal and less formal wear for a ball!)