PDF Glossary
Common PDF terms and definitions explained simply
Glossary terms
- Annotation
- A note, comment, highlight, or markup added to a PDF document without changing the original content.
- Bookmark
- A navigational link in a PDF that takes the reader to a specific page or section within the document.
- Compression
- The process of reducing a PDF file size by optimizing images, fonts, and data structures while maintaining readability.
- Digital Signature
- A cryptographic method to verify the authenticity and integrity of a PDF document, proving who signed it and that it hasn't been altered.
- DPI (Dots Per Inch)
- A measure of image resolution in a PDF. Higher DPI means better quality but larger file size. 72 DPI is standard for screen, 300 DPI for print.
- Encryption
- Security feature that protects PDF content by converting it into unreadable code, requiring a password to access.
- Fillable Form
- A PDF containing interactive form fields (text boxes, checkboxes, dropdowns) that users can fill in digitally.
- Flatten
- The process of merging all layers, annotations, and form fields into a single, non-editable layer in a PDF.
- Font Embedding
- Including font data within a PDF file so the document displays correctly on any device, even without the font installed.
- Linearized PDF
- A PDF optimized for fast web viewing, allowing the first page to display before the entire file is downloaded.
- Merge
- Combining two or more PDF files into a single document while preserving the content and formatting of each.
- Metadata
- Hidden information stored in a PDF file such as author name, creation date, keywords, and software used to create it.
- OCR (Optical Character Recognition)
- Technology that converts scanned images of text into selectable and searchable text within a PDF.
- Page Orientation
- The direction a page is displayed — portrait (vertical) or landscape (horizontal).
- PDF/A
- An ISO-standardized version of PDF designed for long-term archiving, ensuring the document remains readable for years.
- Rasterization
- Converting vector-based PDF content into a pixel-based image, often used when printing or converting to image formats.
- Redaction
- Permanently removing sensitive information from a PDF so it cannot be recovered or viewed.
- Split
- Dividing a single PDF into multiple separate files, either by page ranges or individual pages.
- Watermark
- Text or image placed over or behind PDF content, often used for branding, copyright protection, or marking documents as drafts.
- XFA (XML Forms Architecture)
- An advanced form format in PDFs that supports dynamic layouts and complex data, primarily used in enterprise forms.
Related tools: Merge PDF · Split PDF · Compress PDF · Protect · Sign PDF · Redact
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