Line height refers to the vertical space between lines of text in a paragraph. It is an important aspect of typography that affects readability and overall design. A larger line height can make text easier to read, while a smaller line height can create a more compact appearance. In web design, line height is often specified in CSS using the property line-height. This property can be set using various units, such as pixels or percentages, allowing designers to customize the spacing according to their needs. Proper line height enhances the visual flow of text and improves user experience.