Lily is named after a flower. Coincidence? We think not. Take a look:
She was like a water-plant in the flux of the tides. (1.5.6)
She could not figure herself as anywhere but in a drawing-room, diffusing elegance as a flower sheds perfume. (1.9.9)
She made no reply, but her face turned to him with the soft motion of a flower. (1.12.34)
She was like some rare flower grown for exhibition, a flower from which every bud had been nipped except the crowning blossom of her beauty. (2.13.38)
Check out Lily's "Character Analysis," when we talk about Lily being willingly objectified as a beautiful thing to watch, rather than a real person. Looks like her name fits the bill. Flowers don't really learn or teach or engage or think – but they are pretty. And nice to look at.
Though never explicitly stated House of Mirth, it's clear that distinct social circles do in fact exist. And whichever sphere each character helps to populate is a very telling detail. Lily, Bertha Dorset, Judy Trenor, Gus Trenor, George Dorset – these are all the social elite when the novel begins. Characters like Simon Rosedale are on the fringe of high society and trying desperately to work their way in. Selden prefers to be a spectator, but still spends a good amount of time in the expensive drawing rooms of society's elite. Then take someone like Mrs. Norma Hatch – who's lower down on the social ladder, below even the Gormers – trying to be one of the elite. She is defined by her social status as much as the charwoman or Lily Bart or Gertrude Farish. In a world where social determinism rules the day, social status is your clearest tool of characterization.
It's really more like social occupation. Look at the various jobs that different characters perform in the great social machine. Mrs. Fisher is like a social coordinator, hooking up new money with old, and keeping the party juices flowing. Ned Silverton and Lucius entertain the older, married women and perhaps even keep them happy in bed. The men – George Dorset, Gus Trenor, and Rosedale – are supposed to bring home the bacon and keep quiet. Everyone has a purpose, and each person's social "job" tells us something about his or her character.