In modern China, 美女 is used very casually — shop owners, taxi drivers, and strangers call any young woman 美女 as a friendly greeting, similar to 'miss.' It doesn't necessarily imply actual beauty.
history
The Four Great Beauties (四大美女) of ancient China: Xi Shi, Wang Zhaojun, Diao Chan, and Yang Guifei. Each famous for toppling kingdoms with their beauty.
