Glossary
The chart-type guides lean on a handful of words over and over. This page defines them in plain language, with a small working example for each and a note on where you will run into the term.
If you are new, read How DGMO Thinks first — it covers the ideas. This page covers the vocabulary.
The shape of a file
Nearly every .dgmo file has the same three parts, in this order:
- Line 1 names the chart type and the title.
- Any directives — settings for the whole diagram.
- Any tag groups — named colors you will reuse.
- The content — the actual things being drawn.
The words in bold are defined below.
Line and structure words
Declaration
Writing a thing down for the first time, on its own line. A declaration brings something into existence: a chart type, a node, a task, a tag group.
Line 1 is the chart-type declaration — the chart type (bar) and the title (Doubloons by Month). Jan 42 declares a bar.
The word “declare” carries a rule with it: in most chart types you have to declare something before you can point an arrow at it. You will see phrases like “declare the node first, then indent its edges below it.”
Where you meet it: every guide. Line 1 of every diagram is a declaration.
Directive
A setting that applies to the whole diagram, written on its own line near the top, before the content.
“Directive” and “option” are the same thing. The chart-type guides mostly say “directive”; How DGMO Thinks mostly says “option”. If you have learned one word, you already know the other.
Directives come in two shapes. A bare directive is a single word that switches something on:
A value directive is a word followed by its setting, separated by a space — never a colon:
Many bare directives have an off switch spelled with a no- in front: the legend is on by default, and no-legend turns it off. Guides call these opt-outs, or cosmetic opt-outs when they only affect appearance.
Directives must come before the content. A directive written lower down is usually read as content instead — see What a clean check does and doesn’t tell you.
A few directives work in nearly every chart type. Guides call this set the universal appearance directives: fill-tint (the default), fill-solid, fill-outline, no-title, and no-legend. The fill- family controls how shapes are filled — a soft tint, a full block of color, or an outline with no fill.
Guides often describe a directive by saying it does not exist: “there is no title directive,” “no format or currency directive.” This is telling you not to go looking — that behaviour is decided some other way, usually from your data or from the title line.
Where you meet it: every chart type has its own set. Gantt and PERT have the most; bar and pie have a few.
Flag
Another word for a bare directive, or for a bare word attached to a single line rather than the whole diagram — [Backend] collapsed puts a collapsed flag on one group.
Token
One chunk of a line, with spaces on either side of it. Provision Ship 10bd has three tokens: Provision, Ship, and 10bd.
The word matters because some chart types decide what a line means by looking at the last token. In a gantt chart, the last token is the duration and everything before it is the task name. That is why Provision Ship 10bd gives you a task called “Provision Ship” lasting ten business days — and why an unexpected extra token at the end changes the meaning of the whole line.
Where you meet it: gantt, PERT, bar, line, and anywhere a guide says “positional” or “the last token.”
Bare
Written on its own, with nothing after it. A bare directive is the keyword on its own (today-marker). A bare color is a color name with no color: label in front of it ([Done] green). “Bare” is the opposite of writing key: value.
Where you meet it: kanban, pyramid, ring, gantt, and the directive lists in most guides.
Top-level
Not indented. A top-level line starts at the left edge of the file, in column one. Directives are top-level. So are the outermost items in a hierarchy.
Where you meet it: used throughout to distinguish settings from content.
Attaching extra information
Metadata
Extra facts attached to something you already declared, written as key: value. The key is the name of the fact; the value is the fact itself.
Metadata is how you say “and also” — this person has a role, this task is 80 percent done, this connection carries high traffic.
There are two places to put it, and they mean exactly the same thing.
Same-line metadata goes on the end of the line, after the name. Multiple pairs are separated by commas:
Indented metadata goes on the lines beneath, one pair per line:
Use same-line for one or two facts, indented for several. There is no way to continue a same-line list onto a second line — a line ending in a comma is an error.
The colon is required in metadata. That is one of the two places DGMO uses colons at all; see The Colon Rule.
Where you meet it: almost everywhere. Org and C4 prefer the indented form; gantt, kanban, and the connection-style diagrams usually use same-line.
Key and value
In role: Captain, role is the key and Captain is the value.
Each chart type publishes a known set of keys it understands. Guides call these reserved keys. A key the chart type does not recognise may be quietly ignored rather than flagged, so it is worth checking the guide’s list rather than inventing a key name.
Reserved keys are the mirror image of directives: directives are colon-free settings for the whole diagram, reserved keys are colon-carrying facts about one item.
Trailing color
A color name written at the end of a line to color that one thing, with no key in front of it:
This is fine for a one-off accent. When the color means something — a status, a team, a priority — use a tag group instead so the diagram grows a legend that explains itself.
Only eleven color names exist: red, orange, yellow, green, blue, purple, teal, cyan, gray, black, white. See Colors.
Tags
Tag group
A named set of categories, each with a color. You declare the group once near the top of the file, then label things with it. The diagram grows a legend from the group automatically.
tag Priority as p declares the group. Critical red and Routine green are its members, indented beneath. API p: Critical puts the API in the Critical category, which colors it red and adds a “Priority” legend.
The first tag group you declare becomes the active one, which is the one the legend and any coloring use by default.
Where you meet it: most diagram types that draw distinct things — boxes-and-lines, infra, flowchart, gantt, kanban, timeline, treemap, and more.
Alias
The short name you give a tag group so you do not have to type the long one on every line. In tag Priority as p, the alias is p.
You choose the alias — t and p are conventions, not requirements. Once declared, the alias works as a metadata key anywhere in the file, including on groups and edges.
Where you meet it: everywhere tags are supported. The alias is what you actually type; the full name is what shows up in the legend.
Active tag
Which tag group the diagram uses for coloring and the legend when more than one is declared. The first group declared is active by default; the active-tag directive picks a different one.
Things and connections
Node
One box, circle, or shape in a diagram — a single thing being drawn. Different guides call the same idea by different names depending on what it represents: a participant in a sequence diagram, a table in an ER diagram, a class in a class diagram, a card in kanban, a task in a gantt chart, a page in a sitemap.
Edge
A line or arrow between two nodes. Also called a connection, relationship, arrow, or dependency depending on the chart type.
The arrow’s source is where it starts; its target is where it points. In the example, Harbour is the source of both edges. -cargo-> is a labeled edge — the word between the dashes becomes the text on the line.
Where you meet it: boxes-and-lines, infra, flowchart, C4, sequence, ER, class, state, sitemap, PERT.
Group (container)
Several things drawn together inside a labeled boundary. Written with square brackets. Whatever is indented underneath belongs to it.
The same bracket syntax means “column” in kanban, “swimlane” in gantt, “boundary” in C4, and “category” in scatter charts — but it is always the same idea: these things go together.
Hierarchy words
These come from the way people describe family trees, and they show up wherever one thing sits underneath another.
Take this org chart:
Parent
The thing directly above, that something belongs to. Blackbeard is the parent of Anne Bonny.
Child
The thing indented directly underneath a parent. Anne Bonny and Calico Jack are children of Blackbeard.
Sibling
Two things with the same parent. Anne Bonny and Calico Jack are siblings.
Root
Something with no parent — a top-level line. Blackbeard is the root here. A diagram can have more than one root.
Branch
Anything that has children of its own. Anne Bonny is a branch, because Mary Read sits under her.
Leaf
Anything with no children — the end of a line of descent. Mary Read and Calico Jack are leaves.
The branch/leaf distinction matters most in treemap, where the two are measured differently:
Leaves carry the numbers. A branch’s size is the sum of its leaves, calculated for you — a number written on a branch is ignored, and a leaf with no number renders at zero size. Both of those produce a warning, so you will be told.
Nesting / hierarchy
“Nested” means one thing sits inside or underneath another. “Hierarchy” is the whole tree of parents and children. In DGMO, indentation is what creates both — see How indentation works.
Where you meet these: org, sitemap, treemap, mindmap, family, C4, kanban, and any guide that talks about levels.
Data-chart words
Row
One line of data. In Jan 42, the row has a label and a value.
Series
One set of related numbers running across the whole chart — usually drawn as one line, or one color of bar repeated in every group. A chart with three lines has three series.
Header
A line that names the columns or periods that the rows underneath will line up against.
Axis
The numbered edge of a chart — the bottom edge (horizontal) or the side (vertical). What the axis covers is normally worked out from your data, which is why an axis is worth glancing at after any edit.
Legend
The small key that explains what each color means. Tag groups generate one automatically. no-legend hides it.
Slice / segment
One wedge of a pie or ring chart, or one block of a stacked bar.
Lane
A horizontal band grouping related rows — used in swimlane diagrams and in gantt charts with lane-by.
Words about the tool
Palette
The set of eleven colors currently in use. When you write red, you get the red belonging to your active palette, not a fixed shade. Switching palettes recolors the whole diagram in a way that stays harmonious. See Colors.
Parse
Reading your text and working out what it means. When a guide says “the parser accepts” or “this is a parse error,” it is talking about this step.
Render
Drawing the picture, once the text has been read. A file can parse without complaint and still render something you did not intend — see What a clean check does and doesn’t tell you.
Toggle
A directive that is either on or off, with no value — today-marker, critical-path, no-legend.
Validate / check
Reading the file and reporting anything that cannot be understood. A clean check means the file was readable. It does not mean the diagram is right. This distinction matters enough to have its own section: What a clean check does and doesn’t tell you.
Diagnostic
One message from that check. An error means nothing could be drawn. A warning means something was drawn, but probably not what you meant. Warnings are worth reading — they catch several of the mistakes a plain error check misses.
Infer
Work something out from what you already wrote, instead of asking you to state it. Chart types infer shapes from names, axis ranges from your numbers, and branch sizes from their leaves. When a guide says “inferred from,” it is telling you there is no directive for that thing — change the input and the output follows.
Override
Replace something that was inferred or inherited. A per-item value overrides a whole-diagram directive.
Resolve
Turn what you wrote into the thing it refers to — matching a place name to a location, or a short alias to the full tag group it stands for.
Collapse
Fold a group down so its contents are hidden and it draws as a single shape.
Scope
The stretch of the file where a name means something. “Names are lane-scoped” means the same name in two different lanes refers to two different things.
Canonical
The recommended spelling, when more than one spelling works. Older spellings usually keep working; the canonical one is the one to write in new files.
ISO date
A date written year-first: 2026-03-15. It is unambiguous everywhere in the world, which is why guides recommend it. Other formats are accepted — see Writing Dates.
Words with more than one meaning
A few words are used for different things in different guides. Read them in context.
| Word | In one place | In another |
|---|---|---|
| Branch | Something with children under it (treemap, mindmap) | A line of development in a version-control diagram |
| Anchor | The fixed date or time a countdown or clock is measured from | The point a PERT chart lines its layout up against |
| Row | One line of data in a chart | One key: value line of metadata, or one line of an ER table |
| Header | A line naming the columns the data lines up against | The banner title across the top of the rendered diagram |
| Tag | The tag line that declares a group of categories | The category you then attach to something |
| Group | A bracketed container of items | A tag group, which is a set of named colors |
Comment
A line starting with // that is ignored. Comments must take up the whole line; there is no way to put one at the end of a line of content.