A term that refers to professional women in China who have not found Mr. Right or have not married by their late 20s. A big challenge for today's urban, educated and well-paid Chinese women is that it's hard to find the right man in a society where the husband's social status is traditionally above the wife's. Chinese people often think males should be higher in a relationship in every aspect such as height, age, education and salary. This tradition leads to a phenomenon in which A-grade men marry B-grade women, B-grade men marry C-grade women and C-grade men marry D-grade women. Only A-grade women and D-grade men can't find partners.