Glossary

On this page

Typography is an old trade with too many words: the same thing is "leading" to a designer, "line-height" to a front-end developer, and lineGap inside the font file. This page collects every term the articles on this site use.

The English column is there for searching: with the original word you can find the specification. The last column is a one-liner — follow the link when you want the full story.

Fonts and faces

Term	中文	In one line
font (colloquial)	字体	Sometimes one face, sometimes a whole family — depends on context
font family	字体家族	One design with several weights and styles, e.g. "Inter"
font face	字款	One specific member: Inter Bold, Inter Italic. Usually one file per face
weight	字重	Thickness grade, 100–900 (400 is usually Regular, 700 Bold)
width / stretch	字宽	Narrower or wider versions of the same design, e.g. Condensed
italic	斜体	Genuinely drawn as slanted letterforms
oblique	伪斜体	The upright design slanted by a transform, no separate drawing
variable font	变量字体	One file with continuous axes — endless weights and widths
static font	静态字体	One file per weight (the traditional arrangement)

Why the distinction matters: Fonts, families and faces.

Glyphs and outlines

Term	中文	In one line
glyph	字形	What one character looks like when drawn; a character can have several
outline	轮廓	The Bézier curves of a glyph — filled, they become the stroke
font unit	字体单位	The font's internal coordinate grid, not pixels
em square	em 方框	The design grid whose side equals `unitsPerEm`
hinting	表意指令	Instructions that nudge strokes at small sizes; less common now
tofu	豆腐块	The box shown when a glyph is missing (`.notdef`)
glyph ID / GID	字形索引	The font's internal number for each glyph; `0` is always `.notdef`

Vertical metrics

Term	中文	In one line
baseline	基线	The line Latin letters sit on — also y = 0
x-height	x 高度	Height of a lowercase `x`; strongly affects apparent size
cap height	大写高度	Height of uppercase letters
ascender / descender	升部 / 降部	How far glyphs reach above / below the baseline
leading	行距	The space between lines (designer's word)
line height	行高	Total height one line occupies (CSS's word)
line gap	字体自带行距	A suggested gap stored in the font file

Horizontal spacing

Term	中文	In one line
tracking / letter-spacing	字距	Loosening or tightening all characters evenly
kerning	字偶距	Corrections for specific pairs, typically "AV" or "To"
advance width	字符宽度	The horizontal distance a glyph takes up
side bearing	侧边距	Gap from the outline to the character's left / right edge

Unicode and characters

Term	中文	In one line
code point	码位	A character's number, written `U+0041`
block	区块	A contiguous range of code points, e.g. Basic Latin
assigned	已分配	The code point has an official name (not that a font has its glyph)
combining mark	组合字符	A mark attached to the preceding character, e.g. an accent
variation selector	变体选择符	An extra code point choosing which glyph to use
shaping	整形	Turning a code point sequence into a glyph sequence
fallback	回退	When the current font lacks a glyph, the browser tries the next font

CSS and the web

Term	中文	In one line
font stack	回退栈	The list of names in `font-family`, ending with a generic family
generic family	通用族	`serif` / `sans-serif` / `monospace` / `system-ui` — the browser picks the font
OpenType feature	字体特性	Optional font behaviour behind a four-letter tag, e.g. `liga`, `kern`, `tnum`
subset	子集	Keeping only the characters you need, to shrink the file
layout shift / CLS	布局位移	Text jumping when a webfont arrives late

Fonts and faces#

Glyphs and outlines#

Vertical metrics#

Horizontal spacing#

Unicode and characters#

CSS and the web#