Other walls are called gables.
The parapet is actually a wall that presses the eaves, known as battlements among the people. It generally refers to the low wall where the outer wall of a house is higher than the roof. It is a form of building wall. The parapet is also an important front line of roof waterproofing. In addition to maintaining safety, the main function is to install waterproof bricks at the bottom to prevent water from seeping through the waterproof layer or flooding the roof with rainwater. Of course, it also has an aesthetic effect. It is most common on the roof of a unit building and has become an essential and enclosed part of the building.
There is a sad and touching legend about the parapet wall. An ancient mason was busy at work and had to take his young daughter with him. One day while building the roof, the daughter accidentally fell to her death. . The craftsman was heartbroken. In order to prevent the tragedy from happening again, he built a low wall on the roof, which was later named "parapet".
From then on, in order to prevent similar accidents from happening, a protective wall was built around the roof. In order to commemorate the dead daughter, this kind of wall will be called the parapet wall from now on.