To be able to thoroughly understand Lady Windermere's Fan (LWF), one has to understand what is meant by "Society".
In Victorian England, "Society" could be defined as a "status or interest group regulated by an elaborately coded system of relationships, the main function of which was to provide solidarity and cohesion, as well as to assign position and rank to its members. It was, like all other status groups [...] almost obsessively concerned with access to or exclusion from its ranks [...]" and "[t]he central feature of Society [...] was a tightly regulated code of behaviour which, as much as money or birth, was the defining attribute of Society’s members, for it identified them publicly as ladies and gentlemen. To deviate from these conventions [...] was to relinquish that title and the distinction it bestowed and to place oneself outside Society" (Lady Windermere’s Fan (New Mermaids) by Oscar Wilde (2002–12-20). (2022). Methuen Drama; edition (2002–12-20).
The rules that defined what was constitued as acceptable behaviour, and which regulated both domestic and social life, were referred to as "etiquette" and people in Society prided themselves on abiding by these rules.
Oscar Wilde's plays, however, point out a clear distinction between what people in Society said they did as opposed to what they actually did.