# Ligature

> Source: https://www.infinitelibrary.ai/glossary/ligature

Last updated: 2026-09-06
Category: Typesetting & layout
Also called: fi ligature · Discretionary ligature

A ligature is one glyph joining two or more letters — fi, fl, ff, ffi, ffl — where the separate shapes would collide; typesetting software inserts them.

## Definition

A **ligature** is two or more letters fused into one designed shape. The **standard ligatures** in Latin text are **fi, fl, ff, ffi and ffl**: without them the hook of the *f* crashes into the dot of the *i* or the top of the *l*. They are not decoration; they exist to fix a collision. The ampersand began life as a ligature of *e* and *t*, and the German ß as a long-s and z.

**Discretionary ligatures** — *st*, *ct*, *sp* in some faces — are ornamental and belong in headings or display settings, not running text.

Professional typesetting substitutes standard ligatures automatically through the font's OpenType features. Two rules follow: never letter-space text that contains ligatures, because the joined glyph cannot be spaced apart, and check that the font actually has them — many web and system fonts do not, and a missing ligature is the first thing a trained eye notices on a printed page.

## In Bindery

Bindery’s LaTeX typesetting applies a font’s standard ligatures as it sets the text — the same mechanism that gives its proofs proper fi and fl pairs.

## Related

- [Kerning](https://www.infinitelibrary.ai/glossary/kerning)
- [Typesetting](https://www.infinitelibrary.ai/glossary/typesetting)
- [Embedded fonts](https://www.infinitelibrary.ai/glossary/embedded-fonts)
- [LaTeX](https://www.infinitelibrary.ai/glossary/latex)
- [Turn a Word Document Into a Printed Book](https://www.infinitelibrary.ai/tools/word-document-to-printed-book)
- [Turn a PDF Into a Printed Book](https://www.infinitelibrary.ai/tools/pdf-to-printed-book)
- [Book Publishing Glossary — 59 Terms Defined](https://www.infinitelibrary.ai/glossary)
- [Bindery — the Claude-powered book studio](https://www.infinitelibrary.ai/bindery)

---

More from Infinite Library, as one map for AI agents: https://www.infinitelibrary.ai/llms.txt