Which measurement unit is often used in typography to define text size?

The unit most commonly used in typography to define text size is points. In the field of graphic design and typesetting, points are the standard unit of measurement. One point is equivalent to 1/72 of an inch, which allows for precise control over text size as well as spacing in printed materials. This measurement system has been widely adopted in both traditional printing and digital typography, enabling designers to ensure consistency and clarity in text appearance across various mediums.

While other units like millimeters, picas, and inches are used in different contexts, points have become the established norm specifically for fonts and type sizes. Picas, for instance, are often used to measure the overall layout of pages rather than individual text elements. Thus, points provide a focused and standardized way to communicate text size in design work.