Body lines refer to the contours and shapes that define the structure of a person's body. These lines can be influenced by factors such as genetics, fitness, and posture. They play a significant role in how we perceive body aesthetics and can vary widely among individuals. In the context of art and design, body lines are often used to create visual interest and balance. Artists and designers may study the body lines of the human form, such as those seen in sculpture or fashion design, to enhance their work and convey movement or emotion.