PDF terms are easier to use when the practical difference is clear. These definitions explain what a term means for your next document task.
AcroForm
Interactive PDF form fields that store values such as text, checkbox states, and selected options. Pagestays can fill supported existing fields, but does not create a new form design.
See the related tool ↗Annotation
An object associated with a page, such as a comment, highlight, or link. An annotation is not always part of the page content that a conversion or print workflow retains.
See the related tool ↗Appearance stream
The drawing instructions used to display an object such as a form field. A field can contain a value yet display incorrectly when its appearance is missing or stale.
See the related tool ↗Aspect ratio
The relationship between a page or image width and height. Fitting an image while preserving this ratio avoids stretching faces, letters, and diagrams.
See the related tool ↗Attachment
A separate file embedded inside a PDF or attached to a message. Extracting visible pages is not the same as collecting all embedded attachments.
See the related tool ↗Bleed box
A page boundary used in printing to describe the area including bleed. It differs from the intended trimmed page and from the area a reader normally sees.
See the related tool ↗Bookmark
A named destination that helps readers move through a document. Bookmarks live at the document level and may not survive copying individual pages into a new PDF.
See the related tool ↗Byte
A unit used to measure stored file data. A compressed PDF file size does not describe all the memory needed to render its images in a browser.
See the related tool ↗Certificate
A signed credential used in a public-key system. A visible signature image does not itself supply a certificate or establish a verified identity.
See the related tool ↗Character mapping
Information that connects font glyphs to text characters. If it is missing or unusual, a page can look correct while copied or extracted text is wrong.
See the related tool ↗CMYK
A color model associated with cyan, magenta, yellow, and black printing inks. Converting it to screen-oriented RGB can change appearance, so print-sensitive work needs careful color handling.
See the related tool ↗Compression
A change in how data is represented to reduce storage size. Lossless methods preserve information; lossy methods discard some information and require a quality check.
See the related tool ↗Content stream
Drawing instructions that place text, images, and shapes on a PDF page. A PDF is not simply a screenshot or a word-processing file with a different extension.
See the related tool ↗Crop box
The page rectangle normally used to limit the visible region. Content outside it can remain in the document, so cropping is not secure redaction.
See the related tool ↗Digital signature
A cryptographic signature associated with document data. It can support integrity checks and certificate workflows; it is different from a drawn or typed visible mark.
See the related tool ↗Downsampling
Reducing an image to fewer pixels. It can shrink image-heavy documents but may remove small lettering or fine details that cannot be recovered from the output.
See the related tool ↗DPI
Dots per inch, often used for printer output. People also use the term loosely for image resolution, where pixels per inch is the more precise description.
See the related tool ↗Embedded font
Font data carried inside the PDF so a reader can render the intended shapes. Removing it can reduce portability when the receiving device lacks a suitable font.
See the related tool ↗Encryption
A way to make document contents unreadable without the appropriate key or password. It does not decide whether the person receiving a readable copy will keep it private.
See the related tool ↗Flattening
In this product, turning supported form widgets into fixed page appearances. This removes their interactive fields; it does not certify the document or securely erase all hidden information.
See the related tool ↗Font subset
An embedded font containing only the glyphs needed by a document. A later editing operation may need characters that the subset does not contain.
See the related tool ↗Form field
An interactive location that stores a value. A printed line or empty box in a scanned image is not automatically a form field.
See the related tool ↗Grayscale
An image representation using shades of gray. In Pagestays this is produced by rendering pages, so selectable text and interactive features are lost in the output.
See the related tool ↗Image mask
Data that controls which parts of an image are visible or transparent. Re-encoding an image without handling its mask correctly can change its appearance.
See the related tool ↗Imposition
Arranging source pages on output sheets for printing. A basic N-up layout is one form of imposition, but it does not automatically create a folded booklet sequence.
See the related tool ↗JPEG
An image format commonly used for photographs and smooth color variation. Its lossy encoding can create visible artifacts around sharp text and line art.
See the related tool ↗Linearization
A PDF organization designed to support incremental web viewing. It is about loading order, not a guarantee that the complete file becomes much smaller.
See the related tool ↗Lossless
A data transformation that preserves the represented information. It does not mean an entire document workflow preserves all interactive or structural PDF features.
See the related tool ↗Lossy
An encoding that discards some information to reduce size. Repeated lossy conversions can compound damage, so retain an original for future exports.
See the related tool ↗Media box
The PDF page rectangle describing its underlying physical extent. A different crop box can make the visible area smaller without removing the underlying page content.
See the related tool ↗Metadata
Information describing a document, such as title and author. Removing these fields does not remove identifying words, images, attachments, or annotations.
See the related tool ↗N-up
Placing several original pages on one output sheet. The resulting smaller page images are useful for handouts but should be checked for readable text.
See the related tool ↗OCR
Optical character recognition, which attempts to turn text in an image into machine-readable characters. Pagestays text extraction requires an existing text layer and does not perform OCR.
See the related tool ↗Page label
The human-facing numbering scheme used by a document. It may differ from the physical page position used by a page-range control.
See the related tool ↗Page range
A selection of page positions used for splitting or extracting. Check whether the tool counts physical pages or printed page numbers before using a range from a contents page.
See the related tool ↗Portable Document Format, a format for describing pages and associated document structures. A PDF can contain text, graphics, forms, links, metadata, and other objects.
See the related tool ↗PDF/A
A family of PDF standards for long-term preservation. A normal save or a flattened copy is not proof of conformance; use an appropriate converter and validator.
See the related tool ↗PDF/UA
A family of standards for accessible PDF. Useful accessibility also depends on meaningful structure, reading order, descriptions, and human review.
See the related tool ↗PDF/X
A family of PDF standards for print exchange. A general-purpose browser PDF output is not automatically a print-ready PDF/X file.
See the related tool ↗PNG
A raster image format with lossless compression. It can preserve sharp pixel edges but does not keep a PDF text layer, links, or form behavior.
See the related tool ↗Point
A page measurement used by PDF drawing operations. Page dimensions can be converted from physical units, while rendering resolution separately determines pixel counts.
See the related tool ↗PPI
Pixels per inch, the relationship between image pixels and intended physical size. Increasing a declared resolution does not create real detail absent from the source image.
See the related tool ↗Rasterization
Rendering text and graphics into pixels. It fixes a visual appearance but can remove searchable text, document structure, and interactive behavior.
See the related tool ↗Reading order
The sequence in which content is presented to assistive technology or extracted as text. It can differ from the order a sighted reader infers from columns and visual placement.
See the related tool ↗Redaction
Removing sensitive content so it cannot be recovered from the released file. Drawing a box, cropping a page, or changing metadata is not equivalent to a verified redaction workflow.
See the related tool ↗RGB
A color model based on red, green, and blue channels. It is common in screen rendering; printed results also depend on profiles, paper, and printer behavior.
See the related tool ↗Rotation
An orientation change associated with a page. A viewer can rotate the display without saving a document change, so always reopen an edited output to check.
See the related tool ↗Tagged PDF
A PDF containing structural information about its content. Tags can support headings, tables, reading order, and other accessibility features, but their presence alone is not a complete quality check.
See the related tool ↗Text layer
Machine-readable text stored in a PDF. A scanned page can have a hidden OCR layer, while a visually similar scan may contain only an image.
See the related tool ↗Transparency
A drawing property that lets underlying content show through. Flattening transparency is a different operation from flattening form fields.
See the related tool ↗Trim box
The intended finished page boundary in a print workflow. It can differ from a larger media or bleed box used during production.
See the related tool ↗Vector graphics
Shapes described by drawing instructions rather than a fixed pixel grid. They can remain sharp when scaled, unless a later operation rasterizes them.
See the related tool ↗Watermark
A visible text or image mark placed on a document. It can communicate status or ownership but does not prevent copying or establish access control.
See the related tool ↗Widget
The visible interactive representation of a form field on a page. Flattening supported widgets turns their appearance into fixed page content.
See the related tool ↗XFA
XML Forms Architecture, a form technology distinct from ordinary AcroForm fields. Pagestays does not support XFA, and the document publisher may specify a dedicated viewer.
See the related tool ↗XMP
A metadata framework used by PDFs and other media. A document can contain XMP alongside simpler document-information fields, so metadata cleanup needs to consider both.
See the related tool ↗