A typographic point is a unit used for font size, line height and other typographic distances. In the modern digital convention,Here the inch is 25.4 millimetres. The equation describes the digital convention; historical typographic point systems have not all used that same length. The modern
pt relation also appears among the absolute-length units defined for CSS.[ref]CSS Values and Units Module Level 3 by World Wide Web Consortium. Section5.2: absolute lengths and the pt, in and px equivalences
For example, a font size of 12 typographic points corresponds to a nominal em of one sixth of an inch, approximately 4.2333 millimetres. That sets the outline's scale, rather than the exact ink height of every glyph. A particular x-height or glyph advance can be a different fraction of an em.
The CSS conversion also gives 12 typographic points as 16 CSS pixels. A CSS pixel is a layout unit, so this equality does not promise 16 hardware pixels or a ruler-measured physical height on every screen. Zoom and the mapping to device pixels must be accounted for separately; the device pixel ratio records one part of that mapping.
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In typography, a "point" is a unit of measurement used to specify the size of text and the space between lines or letters. Traditionally, one point is equal to 1/72 of an inch, although in practice, the actual size can vary slightly depending on the type of typesetting system used. Points are commonly used to measure: 1. **Font Size**: The height of the characters in a typeface is measured in points.