Tagged PDF
A PDF carrying an invisible structure tree (headings, paragraphs, tables, figures in reading order) that screen readers navigate. Tags define how a PDF reads, not how it looks.
Full definition →Reference
Glossary
Plain-English definitions of the Word styles, spacing, alignment, and formatting concepts behind cleaning up a document, from heading styles to APA and MLA format. Open any term for the full definition and related tools.
Reading order
The sequence assistive technology reads a document's content — defined by the tag structure, not the visual layout. Untagged PDFs expose raw drawing order, which is why they read scrambled.
Full definition →Alt text (PDF)
The textual description a screen reader speaks for an image, stored on the Figure tag's /Alt entry inside a PDF's structure. Meaningful alt text conveys what the image shows — not the word 'image'.
Full definition →Artifact (PDF)
Content marked for assistive technology to skip: running headers, footers, page numbers, decorative rules. Correct artifact marking is as important as tagging — it keeps furniture out of the reading stream.
Full definition →PDF/UA
ISO 14289 — the technical standard for universally accessible PDFs: complete tagging, correct reading order, metadata, artifact marking, embedded fonts. The spec auditors' machine checks are built on.
Full definition →WCAG
The Web Content Accessibility Guidelines — the standard regulations cite (ADA Title II, Section 508, EAA/EN 301 549). For PDFs, WCAG's document-relevant criteria are met by building to PDF/UA practice.
Full definition →Section 508
The US law requiring federal agencies — and through procurement, their vendors — to make electronic content accessible. The Revised 508 Standards incorporate WCAG 2.0 AA for documents, PDFs included.
Full definition →European Accessibility Act
EU law (applying since June 2025) requiring consumer-facing services — e-commerce, banking, transport, telecoms — to be accessible under EN 301 549, which applies WCAG criteria to documents like invoices, statements, and manuals.
Full definition →Screen reader
Software (JAWS, NVDA, VoiceOver) that speaks digital content aloud for blind and low-vision users. For PDFs it reads the tag structure — which is why untagged files are effectively unreadable.
Full definition →Matterhorn Protocol
The industry checklist enumerating PDF/UA conformance as concrete checkpoints — divided into machine-verifiable checks (what automated tools test) and human-judgment items (like whether reading order makes sense).
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