This document defines and describes different types of lines that can be used in drawing. It discusses that a line represents the trace left by a moving dot and must be longer than its width. Lines can be simple or composed of multiple line fragments. Composed lines include zigzag, wavy, curly, and dashed lines. The document also explores how lines can convey different meanings and emotions based on their direction, intensity, and variations. Horizontal lines express calmness while vertical lines convey strength and oblique lines transmit movement. Curved lines indicate dynamism and joy. Lines also reveal an artist's personality. The document concludes by discussing uses of lines such as dividing space, shading, and creating textures.