Price Waterhouse v. Hopkins was a case that happened a long time ago in the United States.
At the time, there was a lady named Ann Hopkins who worked for a big company called Price Waterhouse. She was very good at her job, but her bosses didn't promote her to become a partner in the company. This made her very sad and she found out that it's because some of her male colleagues said she wasn't feminine enough and they didn't like the way she dressed.
Ann Hopkins did not think this was fair, so she went to court to fight for her rights. She said that the company was discriminating against her because she was a woman and that they should be judged based on her work performance, not how she dressed or acted.
The judges listened to her and they agreed with her! They said that it was not fair for companies to judge people based on their gender or how they acted. This was a very big deal because it helped many women and minorities get more equal opportunities at work.
So, in short, Price Waterhouse v. Hopkins was a court case that helped to stop discrimination against people based on their gender at work.