# What is a ligature?

Source: https://epublab.com/glossary/ligature/ (updated 2026-11-03)

A ligature is a single glyph that joins two or three letters, such as "fi", "fl" or "ffi". Fonts use them for appearance; the underlying text should still be the separate letters.

## Why it matters when you convert a PDF to EPUB

In a PDF, a ligature can come out of text extraction as one special character (U+FB01 for "fi"), as nothing at all, or as the right letters, depending on the font's ToUnicode map. A converter should expand ligatures back into letters so that search, hyphenation and text-to-speech work in the EPUB.