Glossary

This is the reference's vocabulary in one place — every term defined once, the way our parser and renderer actually use it.

In short: the rest of this reference defines each construct where it lives, in context and at length. This page is the fast lane: an A–Z list of the IDML format terms and the Paged renderer terms you will meet elsewhere, each with a one- or two-sentence definition and a link to the chapter that covers it properly. The definitions are ours, grounded in how the code reads each thing — not the spec's glossary. Element and attribute names (the CamelCase ones) are facts of the format and are used as written.

A

AppliedFont — The font a run of text asks for, named as a family string (and paired with a separate font-style name like "Bold"); the renderer resolves it against the fonts it can actually load, falling back when a face is missing. See /docs/typography/fonts-and-faces.

anchored object — A page item (a frame, a shape, an image) attached to a position inside the text so it travels with the words around it instead of floating at fixed page coordinates. See /docs/anchored-inline-objects/anchored-objects.

B

BackingStory — The XML/BackingStory.xml part: a story that holds IDML's tagged-XML structure tree, including any content that has been tagged but not yet placed on a page. Our parser does not read it. See /docs/tagged-xml/the-structured-content-layer.

BasedOn cascade — A style can inherit from a parent named in its BasedOn attribute, so a paragraph, character, object, or table style only overrides the handful of properties it changes and inherits the rest up the chain. See /docs/styles/the-cascade.

Bookmark — A named navigation target in the document, typically pointing at a text destination, that becomes a bookmark entry in exported PDF. See /docs/cross-references-hyperlinks/hyperlinks-and-bookmarks.

C

Cell — One box in a table, sitting at a row/column position and holding its own text or content; cells carry their own formatting and can be styled by a CellStyle. See /docs/tables/rows-columns-cells.

CellStyle — A named, reusable bundle of cell-level formatting (insets, strokes, fills, vertical alignment) applied to table cells through the style cascade. See /docs/styles/table-and-cell-styles.

CharacterStyle — A named, reusable set of character-level formatting (font, size, color, tracking) that a run can apply by reference. See /docs/styles/character-styles.

CharacterStyleRange — A run-level element inside a story: a stretch of text sharing one set of character properties, optionally referencing a CharacterStyle, and wrapping the Content that holds the actual characters. See /docs/stories-text/story-structure.

Color — A <Color> swatch definition in the resource palette, carrying a Model (Process or Spot), a color Space, and channel values; page items reference it by id to fill or stroke. See /docs/color-swatches/colors-and-swatches.

Column — A vertical division of a table; columns carry width and, together with rows, locate each cell. See /docs/tables/rows-columns-cells.

compound path — A single shape made of more than one contour, so an inner loop can cut a hole in an outer one (a donut, a letter "O"); in IDML it is one PathGeometry with several GeometryPathType contours. See /docs/geometry-coordinates/compound-paths.

Condition — A document-level definition of a named tag (with a visibility flag) that can be applied to runs of text to switch them on or off as a group. Our renderer enforces it: text under a condition set to invisible is dropped before layout. See /docs/conditional-text/conditions-and-sets.

conditional text — Runs of text marked with one or more Conditions so a single document can hold several variants and show only the conditions currently visible. See /docs/conditional-text/visibility.

Content — The leaf element inside a CharacterStyleRange that carries the literal text characters of a story. See /docs/stories-text/story-structure.

continuous media — The web's model of content: an endlessly reflowing canvas with no fixed page boundaries, the opposite of paged media. See /docs/foundations/what-is-paged-media.

cross-reference — A reference in the text to another place in the document (a heading, a paragraph) whose displayed text — often a page or chapter number — is derived from the target. See /docs/cross-references-hyperlinks/cross-references-and-index.

D

designmap — designmap.xml, the package's manifest and root: it carries the Document element and points at every other part in the archive, so it is the first thing our parser reads. See /docs/package-anatomy/the-design-map.

display list — The renderer's intermediate output: an ordered list of fills, strokes, images, and glyph runs produced from the laid-out document, which the rasteriser then paints into pixels. See /docs/the-renderer.

DOMVersion — The attribute on the root Document naming the scripting-DOM / format revision the package targets (e.g. 20.0); our parser reads it but does not branch on it. See /docs/round-tripping/version-markers.

drop cap — An enlarged opening character (or characters) of a paragraph that hangs down across several lines, set by DropCapCharacters and DropCapLines on the paragraph. See /docs/typography/drop-caps-and-tabs.

F

FillTint — A per-application tint percentage on a page item's fill: it lightens the referenced swatch toward paper for that fill, independent of any tint baked into the swatch itself. See /docs/color-swatches/gradients-and-tints.

G

GeometricBounds — A page item's axis-aligned bounding box, given as "y1 x1 y2 x2" in its own coordinate space; it is the box, not the true outline (that is PathGeometry). See /docs/geometry-coordinates/geometric-bounds.

GeometryPathType — One contour (one open or closed loop) inside a PathGeometry; more than one of them makes a compound path. See /docs/geometry-coordinates/path-geometry.

Gradient — A swatch that blends between color stops (linear or radial), referenced by page items as a fill or stroke. See /docs/color-swatches/gradients-and-tints.

GraphicLine — A page-item type that is an open path — a drawn line or open curve rather than a closed shape. See /docs/frames-paths/page-item-types.

Group — A page item that contains other page items as a single movable, transformable unit; the group carries its own ItemTransform that composes with its children's. See /docs/frames-paths/groups.

H

Hyperlink — A clickable region of the document (a text span or a page item) that points at a destination — a URL, a page, or a text anchor — and becomes a link in exported PDF. See /docs/cross-references-hyperlinks/hyperlinks-and-bookmarks.

I

IDML — InDesign® Markup Language: Adobe's open, XML-based interchange format for InDesign documents, packaged as a ZIP of human-readable XML parts that describe a layout's structure and intent rather than its pixels. See /docs/foundations/what-is-idml.

idPkg reference — A reference, in the idPkg XML namespace, from the design map to one of the package's separate part files (a spread, a story, the styles); it is how designmap.xml names the other parts. See /docs/package-anatomy/how-parts-reference.

INDD — InDesign's native working file: a compact, proprietary, version-coupled binary that only InDesign fully reads — the closed counterpart to the open IDML. See /docs/foundations/what-is-idml.

ItemLayer — The attribute on a page item naming which Layer it belongs to; the item's visibility and stacking follow that layer. See /docs/layers/the-layer-model.

ItemTransform — A page item's affine transform — a six-number matrix that positions, scales, rotates, or skews the item relative to its parent's coordinate space. See /docs/geometry-coordinates/item-transform.

J

Justification — The paragraph attribute that says how lines align in the column (left, center, right) and whether they are justified (word spaces stretched to fill the line). See /docs/typography/justification-and-linebreaking.

K

Knuth–Plass — The total-fit line-breaking algorithm our composer uses: it weighs all the break opportunities in a paragraph at once to minimise overall raggedness, the way InDesign's Paragraph Composer does, rather than breaking line by line. See /docs/typography/justification-and-linebreaking.

L

Layer — A document-level Layer definition: a named, ordered plane that page items are assigned to, carrying visibility and print flags that gate everything on it. See /docs/layers/the-layer-model.

Leading — The vertical distance from one text baseline to the next; in IDML it rides on the character properties and can be a fixed value or Auto (a multiple of the type size). See /docs/typography/spacing-and-leading.

M

MasterSpread — A reusable spread (the page template) whose items are stamped onto the document pages that apply it, supplying repeating furniture like running headers and page numbers. See /docs/master-spreads-overrides/master-items-and-stamping.

mimetype — The first entry in the IDML ZIP, an uncompressed file whose contents identify the archive as an application/vnd.adobe.indesign-idml-package; our parser checks it when opening the container. See /docs/package-anatomy/zip-container.

N

NextTextFrame — The forward link in a text thread: a TextFrame's attribute naming the Self id of the next frame the story continues into ("n" at the tail). See /docs/stories-text/threading-and-overset.

O

ObjectStyle — A named, reusable bundle of page-item formatting (fill, stroke, text-frame options, effects) applied to frames and shapes through the style cascade. See /docs/styles/object-styles.

overset — Text that does not fit in its frame chain: the leftover lines past the end of the last frame. The text is still fully present in the story part, but our renderer drops the overset lines from the rendered page rather than spilling them. See /docs/stories-text/threading-and-overset.

Oval — A page-item type that is a closed elliptical shape. See /docs/frames-paths/page-item-types.

P

Page — One side of paper within a spread, with its own size and bounds; items sit on the spread but are read against the pages it holds. See /docs/layout-model/spreads-and-pages.

page item — The general term for any drawable object on a spread — a TextFrame, Rectangle, Oval, Polygon, GraphicLine, Group, or placed image — each carrying its own geometry and transform. See /docs/layout-model/page-items-and-stacking.

package / UCF — IDML is a package: a ZIP archive following Adobe's Universal Container Format conventions (a leading uncompressed mimetype, a META-INF folder), not a single flat file. See /docs/package-anatomy/zip-container.

paged media — Content fixed to discrete, bounded pages with precise positions, flowing text, and shared styling — the world IDML describes, and the opposite of the web's continuous media. See /docs/foundations/what-is-paged-media.

ParagraphStyle — A named, reusable set of paragraph-level formatting (alignment, indents, spacing, leading, drop caps) that a paragraph can apply by reference. See /docs/styles/paragraph-styles.

ParagraphStyleRange — A paragraph-level element inside a story: a stretch of text sharing one set of paragraph properties (and optionally a ParagraphStyle), containing the CharacterStyleRange runs that make up its text. See /docs/stories-text/story-structure.

PathGeometry — The element that records a page item's actual outline — anchor point by anchor point with Bézier handles — as one or more GeometryPathType contours, as distinct from its bounding box. See /docs/geometry-coordinates/path-geometry.

PathPointType — One point on a contour: an on-curve Anchor plus its incoming (LeftDirection) and outgoing (RightDirection) Bézier control handles. See /docs/geometry-coordinates/path-geometry.

Polygon — A page-item type that is a closed straight-edged (or freeform) shape. See /docs/frames-paths/page-item-types.

process color — A color built on press from the four C, M, Y, K process inks (Model="Process"); the channel values are the color, converted to screen through an ICC profile. See /docs/color-swatches/spot-and-process.

<?aid?> processing instruction — The instruction at the top of the design map whose target is aid; its pseudo-attributes declare the IDML format style, reader version, feature-set bitmask, and exporting application build. Our parser reads past it without branching on any field. See /docs/round-tripping/version-markers.

R

Rectangle — A page-item type that is a closed rectangular shape; the most common container for placed images. See /docs/frames-paths/page-item-types.

renderer-core — The slim, embeddable rendering layer of the Paged engine (core/crates/paged-renderer and friends) that this reference documents — the part that turns a parsed IDML document into a display list and then into pixels. See /docs/the-renderer.

ResultText — The frozen, export-time string a TextVariableInstance carries: the value InDesign computed the last time it composed the document. The renderer inlines that snapshot verbatim; it does not recompute the variable. See /docs/sections-numbering-variables/text-variables.

Row — A horizontal division of a table; rows carry height and, together with columns, locate each cell. See /docs/tables/rows-columns-cells.

run — Our word for one contiguous stretch of text that shares the same effective character formatting — what a CharacterStyleRange delimits, and the unit the renderer shapes and lines. See /docs/stories-text/why-ranges-not-spans.

S

Self id — The unique identifier on nearly every IDML element (its Self attribute); other elements point at it by id, and our parser uses it to resolve every cross-reference in the package. See /docs/package-anatomy/how-parts-reference.

Spread — A unit of the layout holding one or more facing Pages and all the page items placed across them; the document is a sequence of spreads. See /docs/layout-model/spreads-and-pages.

spot color — A single named ink (a PANTONE, say) mixed to a specific recipe (Model="Spot"); having no screen ink, the renderer previews it through its CMYK alternate rather than its primary space. See /docs/color-swatches/spot-and-process.

SSIM — Structural Similarity, the structure-aware image-difference metric the fidelity gate uses (alongside ΔE2000) to compare the renderer's output against InDesign's reference PDF page by page. See /docs/test-corpus.

Story — The container that holds a body of text independent of how it is displayed: one Stories/Story_*.xml part of paragraphs and runs, referenced by the frames that pour it onto the page. See /docs/stories-text/story-structure.

Swatch — The general term for a named, reusable color entry in the palette — a Color, Gradient, Tint, or mixed ink — that page items reference by id. See /docs/color-swatches/colors-and-swatches.

T

Table — A grid of cells embedded in a story's text flow, organised into rows and columns and styled through TableStyle / CellStyle. See /docs/tables/the-table-model.

TableStyle — A named, reusable bundle of table-level formatting (borders, alternating fills, default cell styles) applied to tables through the style cascade. See /docs/styles/table-and-cell-styles.

tagged XML — IDML's optional structured-content layer: a tree of <XMLElement> tags (held in BackingStory.xml, with vocabularies in Tags.xml and Mapping.xml) that overlays a custom XML structure on the document. Our parser does not yet read it. See /docs/tagged-xml/the-structured-content-layer.

TextFrame — A page item that displays text: it does not contain the text but references a Story through ParentStory and contributes a box for that story to flow into. See /docs/frames-paths/text-frames.

TextVariable — A document-level definition of a named, computed string (file name, chapter number, running header, date) whose VariableType names the rule InDesign would run; instances of it appear in stories carrying a frozen ResultText. See /docs/sections-numbering-variables/text-variables.

threading — Linking text frames into a chain (via NextTextFrame / PreviousTextFrame) so one story flows continuously from frame to frame across the layout. See /docs/stories-text/threading-and-overset.

Tint — A swatch (or a per-use percentage) that lightens a base color toward paper white; a Tint swatch references a base Color plus a percentage, while a swatch-level TintValue scales the color where it is defined. See /docs/color-swatches/gradients-and-tints.

Tracking — Uniform extra (or reduced) space added between characters across a run, measured in thousandths of an em. See /docs/typography/spacing-and-leading.

U

UCF — Universal Container Format, the ZIP-packaging convention IDML follows: a leading uncompressed mimetype entry and a META-INF folder so the archive is self-identifying. See /docs/package-anatomy/zip-container.

V

Vello — The GPU-accelerated 2D vector renderer behind Paged's WebGPU backend; it rasterises the display list on the GPU. The legacy CPU path uses tiny-skia instead. See /docs/the-renderer.

W

WebGPU — The cross-platform GPU API the renderer's primary backend targets (through Vello), the same backend that powers the in-browser live preview. The older CPU rasteriser (tiny-skia) remains as a headless, GPU-free fallback. See /docs/the-renderer.

Δ

ΔE2000 — The perceptual color-difference metric (CIEDE2000) the fidelity gate uses to measure, per pixel and per page, how far the renderer's output drifts from InDesign's reference export; together with SSIM it is the pass/fail number behind a fidelity claim. See /docs/test-corpus.

Frequently asked questions

What's the difference between a spread and a page? A Page is one side of paper — a single leaf with its own size and bounds. A Spread is the unit of layout that holds one or more facing pages and every page item placed across them; the document is a sequence of spreads. The distinction matters because items sit on the spread, not on a page: our parser reads each item's position against the spread, then resolves which page it falls on. See /docs/layout-model/spreads-and-pages.

What is a story in IDML? A Story is the container that holds a body of text independently of how it is displayed — one Stories/Story_*.xml part made of paragraphs and runs. The text lives in the story; a TextFrame does not contain it but references it through ParentStory and supplies a box for it to flow into. One story can thread through several frames across the layout. See /docs/stories-text/story-structure.

What does overset mean? Overset is text that does not fit in its frame chain — the leftover lines past the end of the last frame. The text is still fully present in the story part, so nothing is lost from the document; but our renderer drops the overset lines from the rendered page rather than spilling them outside the frame. See /docs/stories-text/threading-and-overset.

Why do these definitions sometimes differ from Adobe's spec glossary? Because they are ours. Each definition here describes how the Paged parser and renderer actually treat a construct — what we read, what we resolve, and what we deliberately skip (BackingStory, for instance, or tagged XML). Element and attribute names like GeometricBounds or ParentStory are facts of the format and are used as written, but the explanations are written from the renderer's point of view rather than restated from the specification. See /docs/foundations/what-is-idml.