Reference
Font Glossary
Plain-language explanations of the typography terms you'll run into when choosing and pairing fonts.
The 5 Font Categories
Every font on ProFont falls into one of five broad categories, based on the shape and structure of its letterforms.
Browse each category directly: Serif, Sans-Serif, Display, Handwriting, Monospace.
X-Height
X-height is the height of a font's lowercase letters, measured from the baseline to the top of a letter like "x", excluding ascenders and descenders. Fonts with a tall x-height feel larger and more legible at small sizes; fonts with a short x-height feel more elegant and classical.
Kerning & Tracking
Kerning adjusts the space between two specific letters, correcting awkward gaps like the one between "A" and "V". Tracking (also called letter-spacing) adjusts the space evenly across an entire word or block of text.
Good kerning is usually built into a well-designed font automatically. Tracking is something you control yourself, tightening it for large headlines, or loosening it for small uppercase labels like the ones used throughout our monospace font pages.
Font Weight
Font weight describes how thick or thin a letterform's strokes are, from Thin (100) to Black (900). Most Google Fonts include several weights in one family, like Inter, which offers nine.
Variable Fonts
A variable font packs every weight, and sometimes width or slant, into a single font file instead of a separate file per weight. This means a site can use 5 different weights of a font while only loading one file, which is faster and more efficient. Inter and Montserrat are well-known examples of variable fonts on Google Fonts, and you'll find the full weight range listed on each font's individual page.
Ligature
A ligature is a single glyph that combines two or more letters into one connected shape, most commonly seen with letter pairs like "fi" or "fl" where the letters would otherwise collide or look awkward next to each other. This is especially visible in serif and handwriting fonts.
flight
Font Pairing
Font pairing is the practice of combining two or more fonts, usually one for headings and one for body text, that complement each other through contrast in style, weight, or structure. See our full guide on how to pair fonts like a pro, or browse pairing suggestions on any individual font page.
Ascender & Descender
An ascender is the part of a lowercase letter that rises above the x-height, like the vertical stroke on "b", "d", or "h". A descender is the part that drops below the baseline, like the tail on "g", "p", or "y".
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OFL License
The SIL Open Font License (OFL) is the license most Google Fonts are released under. It allows anyone to use, modify, and redistribute the font for free, including in commercial projects, without paying royalties or crediting the designer, though attribution is always appreciated. A smaller number of fonts on Google Fonts use the Apache License instead, which has similarly permissive terms. Read our full guide on font licensing explained for commercial use for a complete breakdown of what you can and can't do, or see our guide on free vs. premium fonts.
Web-Safe Fonts
Web-safe fonts are a small set of fonts, like Arial, Times New Roman, and Verdana, that come pre-installed on nearly every device, guaranteeing they'll display correctly without loading anything extra. Google Fonts solved this same problem in a different way: instead of relying on fonts already on someone's device, it hosts the font files itself and lets any site load them instantly, giving designers access to thousands of fonts instead of a handful. See our guide on whether Inter is a good font for a website for more on choosing web fonts.
Font Family vs. Typeface
These terms are often used interchangeably, but technically differ. A typeface is the overall design, like Helvetica. A font family is that typeface's full set of weights and styles, like Helvetica Regular, Helvetica Bold, and Helvetica Italic together. In everyday use, most people say "font" to mean either one, and that's fine, but now you know the technical difference. Explore full font families by category, or see how sizing and weight choices apply in our guide on best fonts for a resume.