# Glossary

## Purpose

Shared vocabulary so terms mean one thing across all projects.

## Decisions

### Terms

| Term | Meaning |
|---|---|
| **Concentric** | Nested rounded corners share a centre, so the inner radius is the outer radius minus the gap, never below zero. See [Radius](../foundations/radius.md). |
| **Control** | An interactive element such as a button, text field, switch or slider. |
| **Floating layer** | A menu, popover, toast, tooltip or dialog that sits above the page and so has a shadow. See [Elevation and Depth](../foundations/elevation-and-depth.md). |
| **Hue** | A colour family, such as violet or teal. See [Colour Palette](../foundations/colour-palette.md). |
| **Medium** | The default control size, 34px. The others are Small (28px) and Large (40px). See [Sizing](../foundations/sizing.md). |
| **Pressed tier** | The fourth neutral fill, `#322f2c`, used when something is pressed. |
| **Role** | What a colour is for: primary (violet), danger (red-pink), warning (orange), success (emerald), info (blue). See [Colour](../foundations/colour.md). |
| **Stand-out treatment** | The gradient used only for premium or highlighted things. See [Colour](../foundations/colour.md). |
| **Step** | A numbered shade of a hue, 100 to 900, such as `violet-600`. See [Colour Palette](../foundations/colour-palette.md). |
| **Throbber (spinner)** | The gradient ring that turns clockwise to show something is loading. |
| **Tier** | One of the flat neutral background levels: background, above-background, background-accent and the pressed tier. |
| **Token** | A named value (a colour, size, radius or timing) used instead of a raw number. See [Token Architecture](../tokens/token-architecture.md). |
| **Touching rule** | Elements with no gap between them are square where they meet; rounded corners appear only on outside edges or where there is a gap. |
| **Trackpad card** | A card with a row of tabs on top and/or a row of buttons along the bottom that butt against the card body. See [Containers](../components/containers.md). |