Lounge is an aesthetic that draws on a lot of inspiration from the late 50's/early 60's space age/Tiki Bar aesthetic one would often see in Las Vegas around that times.
Lounge visuals often draw inspiration from Rockabilly culture, the 60's Tiki bar scene, Casino sights and sounds, 60's bowling alleys, and just an overall playful and fun atmosphere with a little bit of an edge and a dash of sleaze to it.
A lot of Lounge fashion for men include bowling shirts, khakis, Bermuda shorts, and a lot similar fashion elements to Vacation Dadcore, but can also include funky-patterned, light-color suits as well. In short, as long as you look like you just walked of Guy Fieri's closet, you're on the right track to rocking the Lounge look.
Female Lounge fashion can include brightly colored and patterned skirts/pants and light, flowy tops or can be brightly colored/patterned and light/flowy dressed with long sleeves on them, almost taking on a classier version of Rockabilly fashion.
Lounge music is a type of easy listening music popular in the 1950s and 1960s. It may be meant to evoke in the listeners the feeling of being in a place, usually with a tranquil theme, such as a jungle, an island paradise or outer space. The range of lounge music encompasses beautiful music–influenced instrumentals, modern electronica (with chillout, and downtempo influences), while remaining thematically focused on its retro-space-age cultural elements. The earliest type of lounge music appeared during the 1920s and 1930s, and was known as light music. In the 21st century, the term lounge music may also be used to describe the types of music played in hotels (the lounge, the bar), casinos, supermarkets, several restaurants, and piano bars. The 50's and 60's-style Lounge music aesthetic did, however, see a bit of a resurgence in the mid-to-late 90's and may have partially inspired some of the designs often associated now with.