Font Terms and Typography Glossary

The partially enclosed, somewhat rounded negative space in characters such as "n", "C", "S", or "e". The size of the aperture affects readability, especially at small sizes.

A horizontal stroke that is free on one end, such as the top of "T" or the horizontal strokes of "E" and "F".

The part of lowercase letters (like b, d, h, k, l) that extends above the x-height. Ascender height significantly impacts the overall proportion of a typeface.

An imaginary line drawn through the thinnest parts of a letter. Determines if a typeface is old-style (angled axis), transitional (semi-vertical), or modern (vertical axis).

The invisible line upon which most letters sit. Descenders extend below the baseline. Critical reference point for vertical alignment in typography.

Mathematical curves used to define the outlines of glyphs in digital fonts. TrueType uses quadratic Bézier curves, while PostScript/OpenType can use cubic Bézier curves.

A font format where each glyph is stored as a grid of pixels at specific sizes. Not scalable without quality loss, largely obsolete except for screen fonts.

The imaginary area that encompasses each character in a font, historically the metal block in letterpress printing. Defines character boundaries and spacing.

A heavier weight of a typeface, typically used for emphasis. Usually 700 weight in CSS font-weight scale.

The curved, fully enclosed or partially enclosed part of letters like "b", "d", "o", "p", "q", and "g".

A compression algorithm developed by Google, used in WOFF2 fonts to achieve 30% better compression than WOFF's gzip compression.

The height of capital letters from the baseline to the top of flat capitals like "H" and "I". May differ from ascender height.

A single letter, number, punctuation mark, or symbol within a font. Can have multiple glyphs (visual representations).

The complete collection of characters available in a font, including letters, numbers, punctuation, and symbols across all supported languages.

A font format that supports multi-colored glyphs, gradients, and even bitmap images within characters. Formats include SVG, COLR, and SBIX.

A narrower version of a typeface where characters are compressed horizontally, used to fit more text in limited space.

The difference in stroke thickness within a letterform, between thick and thin strokes. High contrast indicates modern typefaces, low contrast indicates geometric sans-serifs.

The enclosed or partially enclosed circular or curved negative space within letters like "o", "e", "c", "a", or "s".

The horizontal stroke that connects two sides of a letter, as in "A", "H", "e", or "f".

A CSS rule that allows custom fonts to be loaded on a webpage, specifying the font family name, source files, and optional properties like weight and style.

The part of lowercase letters (like g, j, p, q, y) that extends below the baseline. Descender depth affects line spacing requirements.

A Mac OS X font format that packages TrueType fonts in a data fork resource instead of the resource fork. macOS-specific, not cross-platform.

A mark added to a letter to change its pronunciation or meaning, such as accents (é, ñ), umlauts (ü), cedillas (ç), or tildes.

A classification of serif typefaces characterized by extreme contrast between thick and thin strokes, vertical stress, and hairline serifs. Also called Modern. Examples: Bodoni, Didot.

A typeface designed for use at large sizes in headlines, titles, and signage rather than body text. Often more decorative with unique features.

A relative unit of measurement equal to the current font size. In a 16px font, 1em = 16px. Named after the width of the capital "M" in metal type.

A long horizontal dash typically the width of the letter "M", used for punctuation to indicate breaks in thought or to set off parenthetical statements.

The conceptual square that defines the design space of a glyph. Typically 1000 units (Type 1) or 2048 units (TrueType/OpenType).

A font that is included directly within a document (like PDF) or application, rather than requiring separate installation on the system.

A unit of measurement equal to half an em, traditionally the width of the capital "N".

A compact font format designed by Microsoft exclusively for web use. Only supported in Internet Explorer, now obsolete.

A wider version of a typeface where characters are stretched horizontally, opposite of condensed.

The enclosed counter space in a lowercase "e", sometimes also referring to the small counter in the lowercase "a".

A backup font specified in CSS font-stack to display if the primary font fails to load or doesn't contain required characters.

A collection of related typefaces that share common design characteristics but vary in weight, width, or style. Example: Helvetica family includes Regular, Bold, Italic, etc.

The tapered or curved end of a stroke that does not terminate in a serif, often seen in "a", "c", "e", "f", and "r".

A web performance issue where text is invisible while a web font loads, creating blank spaces until the font downloads. Can be controlled with font-display property.

Technically a specific size, weight, and style of a typeface. In digital typography, often used interchangeably with typeface to mean the entire family.

Instructions embedded in a font to improve rendering at small sizes or low resolutions by aligning curves to pixel grids. Critical for screen rendering.

A list of fonts specified in CSS (font-family), with fallbacks for each if the previous font is unavailable. Example: "Arial, Helvetica, sans-serif"

The process of creating a smaller font file containing only the characters (glyphs) needed for specific content, reducing file size significantly.

The thickness or boldness of characters in a font, typically ranging from 100 (Thin) to 900 (Black) in CSS font-weight scale.

A free, open-source font editor used for creating, modifying, and converting fonts in various formats including TTF, OTF, and WOFF.

When text briefly appears in a fallback font before the web font loads and replaces it. Less jarring than FOIT, preferred for user experience.

A classification of sans-serif typefaces based on simple geometric shapes like circles, squares, and triangles. Example: Futura, Avant Garde.

The visual representation of a character. A single character may have multiple glyphs (ligatures, alternates, swashes). Example: letter "a" may have standard and stylistic alternate glyphs.

An OpenType feature (GSUB table) that replaces one or more glyphs with alternate glyphs, enabling ligatures, stylistic sets, and contextual alternates.

An early classification of sans-serif typefaces from the 19th century, characterized by slight stroke contrast and closed apertures. Example: Akzidenz Grotesk.

The thinnest stroke in a typeface, often seen in high-contrast designs like Didone serifs. Named after the thin lines in copperplate engraving.

A typographic technique where punctuation marks (quotes, hyphens) are positioned partially or fully outside the text margin for optical alignment.

A classification of typefaces (serif and sans-serif) based on Renaissance letterforms, with organic, calligraphic qualities and visible stroke contrast. Example: Gill Sans, Centaur.

Small notches or indents cut into letters where strokes meet to prevent ink from pooling during printing. Prominent in fonts like Bell Centennial.

A slanted style of typeface, traditionally with calligraphic characteristics different from the roman (upright) form. True italics are redesigned, not just slanted.

How letters connect in scripts like Arabic, where characters change form based on their position (initial, medial, final, isolated).

Text alignment where both left and right edges are aligned (flush), with spacing adjusted between words and sometimes between letters.

The adjustment of space between specific pairs of characters (like AV, WA, To) to achieve visually consistent spacing and improve aesthetics.

Data within a font (kern table) that specifies spacing adjustments for specific character pairs. Can contain thousands of kerning pairs.

The vertical space between lines of text, measured from baseline to baseline. Named after strips of lead used in metal type. In CSS, line-height.

A downward slanting stroke, as in the tail of letters "K", "R", and sometimes "Q".

Two or more characters combined into a single glyph for improved appearance or to avoid collisions. Common ligatures: fi, fl, ff, ffi, ffl.

Numerals that align with the cap height and baseline, creating a uniform height. Used in tabular data, headlines. Also called uppercase figures.

The stroke connecting the bowl and loop of a double-story lowercase "g".

The lower enclosed or partially enclosed counter in a double-story lowercase "g".

Uppercase or capital letters, derived from ancient Roman inscriptional capitals.

The measurements that define how a font is positioned and spaced, including sidebearings, kerning pairs, and vertical metrics.

Lowercase letters, developed from medieval cursive writing styles.

A typeface where every character occupies exactly the same horizontal width. Essential for code, tables, and ASCII art. Example: Courier, Consolas.

An Adobe font technology (now largely superseded by Variable Fonts) allowing interpolation between different font designs on axes like weight and width.

A refined classification of sans-serif typefaces with uniform stroke width and neutral appearance. Example: Helvetica, Univers, Arial.

A slanted version of a roman typeface, created by algorithmically slanting the upright letters rather than redesigning them (unlike true italics).

Numerals with varying heights that blend with lowercase text, having ascenders (6, 8) and descenders (3, 4, 5, 7, 9). Also called text figures or lowercase figures.

A cross-platform font format developed by Microsoft and Adobe (1996), supporting advanced typography features through layout tables (GPOS, GSUB).

Advanced typographic capabilities in OpenType fonts activated through feature tags: ligatures (liga), small caps (smcp), stylistic sets (ss01-ss20), etc.

A font file format (.otf extension) using PostScript (CFF) outlines within the OpenType specification. Supports all OpenType features.

A font where glyphs are defined by mathematical curves (vectors) rather than pixels, allowing smooth scaling to any size without quality loss.

The amount that curved and pointed letters (O, A, V) extend slightly beyond the baseline or cap height to appear optically aligned with flat letters.

A PostScript Type 1 font file format containing the actual glyph outlines in binary format. Used on Windows with .pfb extension.

A file containing metrics information (widths, kerning) for Type 1 fonts on Windows systems. Used alongside .pfb files.

A unit of measurement for font size. One point equals 1/72 of an inch (approximately 0.353mm). Standard measurement in print typography.

A page description language developed by Adobe, forming the basis of Type 1 fonts and CFF outlines in OpenType fonts. Uses cubic Bézier curves.

A typeface where characters have varying widths based on their design (narrow "i", wide "m"). Standard for most fonts except monospace.

The process of converting vector font outlines into pixels for display on screen or printing, using hinting and anti-aliasing for quality.

The upright, non-italic style of a typeface. The standard, default form of most fonts.

A typeface without serifs (the small decorative strokes at the end of letter strokes). Considered more modern and clean. Example: Helvetica, Arial.

The small decorative strokes or projections at the end of the main strokes of letters. Aids readability in print. Example: Times New Roman, Georgia.

The curved stroke projecting from a stem, as in "h", "m", "n", and "r".

The space on either side of a glyph within its em square, affecting letter spacing. Also called side spacing or padding.

A classification of serif typefaces with thick, block-like serifs of uniform weight. Also called Egyptian or square serif. Example: Rockwell, Courier.

Capital letters designed to be approximately the height of lowercase letters (x-height), used for acronyms, headers. True small caps are optically designed, not just scaled capitals.

The main curved stroke of the letter "S", from top to bottom.

A small projection from a curved stroke, smaller and less pronounced than a serif. Often seen on "G", "b", or "a".

The main vertical or diagonal stroke of a letter, forming its primary structure.

The angle of the axis in a curved letter, indicating where the thick and thin strokes occur. Vertical stress is modern, angled stress is old-style.

Any line that makes up a character, whether vertical, horizontal, diagonal, or curved. The fundamental building block of letterforms.

An OpenType feature providing alternative glyph designs for aesthetic variation. Accessed through stylistic sets (ss01-ss20) or character variants (cv01-cv99).

Characters set in a smaller size and positioned below the baseline, used in chemical formulas (H₂O) and mathematical notation.

Characters set in a smaller size and positioned above the baseline, used for footnotes, ordinals (1ˢᵗ), and exponents (x²).

A font format using Scalable Vector Graphics, capable of color and gradients. Deprecated in browsers in favor of WOFF/WOFF2 with COLR/CPAL tables.

Decorative extensions or flourishes on letterforms, often on capitals or script italics. Typically alternates activated through OpenType features.

A font that is pre-installed on a user's operating system, available without downloading. Examples: Arial, Times New Roman, Helvetica (macOS).

Numerals designed with equal width (monospaced) for proper alignment in tables, spreadsheets, and financial data. Also called lining figures.

The descending or extending stroke on letters like "Q", "K", "R", or the descender of "y".

The end of a stroke that does not have a serif. Can be vertical, horizontal, angled, or curved (finial).

A typeface designed for use at small sizes in body text (8-14pt), optimized for readability with generous x-height and open counters.

The dot above the lowercase letters "i" and "j". Also called a jot or superscript dot.

The uniform adjustment of space between all characters in a block of text, affecting overall density. Also called letter-spacing in CSS.

A classification of serif typefaces between Old Style and Modern, with increased contrast and more vertical stress. Example: Times New Roman, Baskerville.

A font format developed by Apple (1980s) and Microsoft using quadratic Bézier curves for outlines. Forms the basis of TTF and TrueType-flavored OpenType fonts.

The file extension (.ttf) for TrueType font files, widely supported across Windows, macOS, and Linux. Can be wrapped in OpenType format.

Adobe's PostScript font format (1985) using cubic Bézier curves. Predecessor to OpenType, limited to 256 glyphs. Now largely obsolete.

The overall design of a set of characters, encompassing all weights, widths, and styles of a font family. The artistic/aesthetic concept vs. font (the delivery mechanism).

The art and technique of arranging type to make written language legible, readable, and appealing. Encompasses font selection, spacing, hierarchy, and layout.

A typeface design where uppercase and lowercase letters share the same height, blurring the distinction between majuscule and minuscule forms.

A universal character encoding standard that assigns unique numbers (code points) to over 149,000 characters from all writing systems worldwide.

A subdivision of the em square used to measure horizontal spacing in fonts. Typically 1000 or 2048 units per em.

A single font file that contains multiple variations along design axes (weight, width, slant, optical size). Reduces HTTP requests and file size compared to loading multiple font files.

The point at which two strokes meet at the bottom of a letter, forming a V shape, as in "V", "W", "v", "w", "A", or "M".

A font specifically designed or converted for use on websites via CSS @font-face. Typically in WOFF2, WOFF, or TTF/OTF formats.

The thickness of a typeface's strokes, from thin/light (100-300) to regular (400) to bold/black (700-900). CSS uses numeric scale 100-900.

How compressed (condensed) or extended the characters in a typeface are horizontally. Separate from weight.

A compressed font format designed specifically for web use, using gzip compression. Supported by all modern browsers. Superseded by WOFF2.

The second version of WOFF using Brotli compression, achieving 30% smaller file sizes than WOFF. The recommended format for modern web fonts (97%+ browser support).

The height of lowercase letters without ascenders or descenders, measured from the baseline to the top of lowercase "x". Critical factor in readability.