The baseline is the invisible line upon which letters rest. It’s used as a point from which other elements are measured, such as [line-height](/glossary/line_height_leading) and [x-height](/glossary/x_height).

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![On the left, the word “hey” set in large type, with its vertical metrics shown and the baseline highlighted. On the right, a paragraph of smaller type, with the baseline shown for each line.](images/thumbnail.svg)

</figure>

A baseline grid refers to the vertical space between the baselines in a block of text; e.g. a 16 pixel baseline grid means there’s a baseline every 16 vertical pixels.