A line is a straight, one-dimensional figure that extends infinitely in both directions. It has no thickness and is often represented visually by a straight mark between two points. In geometry, lines are fundamental elements used to define shapes and angles. They can be horizontal, vertical, or diagonal, depending on their orientation. In art and design, lines play a crucial role in creating structure and guiding the viewer's eye. Different types of lines, such as curved lines, dotted lines, or zigzag lines, can evoke various emotions and styles. Artists and designers use lines to convey movement, texture, and depth in their work.