# What is Dublin Core metadata (dc:*)?

Source: https://epubcc.com/glossary/dublin-core-metadata/ (updated 2026-11-04)

EPUB metadata uses Dublin Core elements in the package document: dc:identifier, dc:title and dc:language are required, and dc:creator, dc:date, dc:publisher and others are optional. EPUB 3 also requires a dcterms:modified timestamp.

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

A PDF often has a useless internal title (a file name like "Microsoft Word - draft3.docx") or none. A converter has to choose a real title, detect the language of the text for dc:language (which drives hyphenation and text-to-speech) and generate a stable unique identifier.

How EpubCC handles it: dc:title is the PDF's metadata title when it is not junk, otherwise a heading from the first three pages, then the largest heading in the book, and only then "Untitled", never a machine-made file name. dc:language is detected from the script and common words of the text, dc:creator comes from the PDF metadata when it has one, and dc:identifier is a UUID derived from the content.