Glossary

Short definitions for the terms you'll meet across the diagram type pages and the guides. Each entry is a quick read; for the full picture, follow the links into diagram types or guides.

• Class diagram — A diagram of object-oriented classes, their fields and methods, and the relationships between them.
• ER diagram — An entity-relationship diagram for database schemas. Shows tables, columns, primary and foreign keys, and the cardinality of each relationship.
• Flowchart — A diagram that uses boxes and arrows to show the steps of a process and the decisions that branch it.
• Gantt chart — A schedule diagram with horizontal bars representing tasks over time, plus dependencies and milestones.
• Mermaid theme — One of four built-in colour palettes Mermaid uses to render diagrams — default, dark, forest, neutral.
• Mindmap — A hierarchical idea map. A tree of nodes radiating from a central root, used for brainstorms and scope outlines.
• securityLevel — A Mermaid initialization option that controls how aggressively the library sanitises rendered output.
• Sequence diagram — A diagram that shows messages exchanged between actors over time, drawn with vertical lifelines and horizontal arrows.
• State diagram — A diagram that shows the discrete states an entity can be in and the events that move it between states.
• SVG vs PNG — Two image formats for exporting a Mermaid diagram. SVG is vector and infinitely scalable; PNG is raster and fixed-resolution. Most of the time, SVG is the right answer.