---
title: Glossary
description: One-line definitions for the words these docs use, one meaning per word.
sidebar: { label: Glossary }
---

The package list named a lot of parts. This page pins down the words around them. Each word has one meaning across the site.

## Writing components

| Term | Meaning |
| --- | --- |
| component | A function in a `.tsrx` file whose body is markup, written `function Counter() @{ ... }`. |
| TSRX | The file format for components: TypeScript plus markup and `@if`, `@for`, and `@try` blocks. |
| state | A value from `state()` that you read and write as a plain variable, like `count`. |
| computed | A value from `computed()` that Markless derives from state. |
| shared | State from `shared()` that many components reach without props. |
| storage | A string value from `storage()` that Markless saves in `localStorage`. |
| element handle | A reference from `element()` to a tag in the markup. |
| key | The identity of each row in an `@for`, as in `key item.id`. |
| async boundary | An `@try` block with `@pending` and `@catch` around an async read. |

## Where a component renders

The compiler does its work at build time. The compiled component then renders wherever you need it. The model is the same in every place.

| Term | Meaning |
| --- | --- |
| browser-only | `render()` from `@markless/core` mounts the app in the browser. The component body runs once there. You need no server. |
| client render | Another name for browser-only rendering. The test helper `render()` uses it. |
| server render | `renderToString()` turns components into HTML on a server. The component body runs on the server and zero times in the browser. |
| multi-page app | An app built with `@markless/router`: file routes, links, and pages rendered through Nitro, which deploys to many hosts. |
| prerender | HTML made at build time. Demos turn it on with `MARKLESS_PRERENDER=1`. Treat it as a preview feature. |
| test render | `@markless/vitest-browser` renders a component in a browser test, either mounted directly or through a server render. |
| native host | Proofs in the repo drive UIKit and AppKit controls with the same model. They are proofs, not a feature you can use. |

## How it works

| Term | Meaning |
| --- | --- |
| compiler | The build step that reads `.tsrx` files. It plans the state, the updates, and which code runs on which event, before the app runs. |
| symbol | One piece of code that the compiler split out, like one click handler. |
| chunk | A file that holds symbols. The browser loads a chunk the first time it needs one of them. |
| packing | The production build step that groups symbols into fewer chunks. It is on by default. Set `packing: false` to turn it off. |
| state graph | The map of which computed values and which page updates read each piece of state. |
| payload | In server output, the data next to the HTML. `markless/state` scripts hold the values. `markless/view` scripts say which element does what. |
| container | In server output, the element with the `data-async-container` attribute. It wraps the HTML and its payload. |
| resumer | The small inline script in server output. It waits for the first interaction and then loads the code it needs. A page with no interactions gets no resumer. |
| resume | The browser continues from server HTML and its payload. It does not run the component body again. |
| hydrate | What many other frameworks do: run components again in the browser to attach events. Markless doesn't. |

## Tooling

| Term | Meaning |
| --- | --- |
| diagnostic | A compiler message with a code, a reason, a suggested fix, and a link. |
| `markless-allow` | A comment that silences one warning, with a reason: `// markless-allow CODE: reason`. |
| `TS91001` | The error code that `pnpm typecheck` and the editor use for a `.tsrx` file that does not parse. |

**Next:** Which commands create and build an app? [CLI →](/reference/cli)