A font family is a group of related typefaces that share a common design but vary in style, weight, or size. For example, the Arial font family includes regular, bold, italic, and bold italic versions. Each style serves different purposes, such as emphasizing text or creating a specific visual effect. Font families are categorized into several types, including serif, sans-serif, script, and monospace. Serif fonts have small lines or decorations at the ends of their letters, while sans-serif fonts do not. Understanding font families helps designers choose the right typeface for their projects, enhancing readability and aesthetic appeal.