Lines in geometry can be categorized into several types based on their characteristics. The most common types include straight lines, which have no curves and extend infinitely in both directions, and curved lines, which bend and change direction smoothly. Another type is parallel lines, which run alongside each other and never intersect, while perpendicular lines intersect at a right angle (90 degrees). Additionally, there are horizontal lines, which run left to right and are parallel to the ground, and vertical lines, which run up and down and are perpendicular to horizontal lines. Diagonal lines slant between horizontal and vertical lines, creating angles. Each type of line plays a crucial role in various fields, including art, architecture, and mathematics.