# Glossary (/docs/reference/glossary)

> One meaning per term: startupbuilder.dev terms quoted and linked, terms these docs define, and mdxui-only terms marked provisional.

startupbuilder.dev, its sites and these docs share one vocabulary. A term startupbuilder.dev defines is quoted here, never redefined. Earlier meanings of each term, and what became of them, are under Maintainers › [Prior definitions](https://next.mdxui.dev/docs/maintainers/prior-definitions).

## From startupbuilder.dev

  - **App** ([definition](https://startupbuilder.dev/business/nouns/app)): An App is an Interface where people work with a Product’s Nouns and Verbs through screens, backed by its API.
  - **Brand** ([definition](https://startupbuilder.dev/business/nouns/brand)): A Brand is a name, a voice, a logo, and a style under which a Startup makes Offers.
  - **Component** ([definition](https://startupbuilder.dev/business/nouns/component)): A Component is a named block of a Page, such as a hero, a pricing table, or a form, filled from records through typed props.
  - **Dashboard** ([definition](https://startupbuilder.dev/business/nouns/dashboard)): A Dashboard is one unified view of a scope, rendered as Markdown for Agents, screens for Humans, and JSON for native clients.
  - **Domain** ([definition](https://startupbuilder.dev/business/nouns/domain)): A Domain is a hostname that points at a Thing, with a role, a status, and a lifecycle tracked as data.
  - **Interface** ([definition](https://startupbuilder.dev/business/nouns/interface)): An Interface is how a person or an Agent reaches a Product: an API, MCP server, CLI, SDK, Site, or App.
  - **Offer** ([definition](https://startupbuilder.dev/business/nouns/offer)): An Offer is a Product, under a Brand, at a price, on terms, made by a Startup.
  - **Page** ([definition](https://startupbuilder.dev/business/nouns/page)): A Page is an addressable page of a Site, of a named type such as pricing, about one Thing or each member of a Collection.
  - **Product** ([definition](https://startupbuilder.dev/business/nouns/product)): A Product is what a Customer gets from a Startup, with a promise the Customer can rely on.
  - **Site** ([definition](https://startupbuilder.dev/business/nouns/site)): A Site is a website as a Thing: its Pages, navigation, and Brand, served on one or more Domains.
  - **Startup** ([definition](https://startupbuilder.dev/business/nouns/startup)): A Startup is the smallest business that can be moved, promoted, or sold on its own, with its own Products, Offers, Customers, and P&L.
  - **Template** ([definition](https://startupbuilder.dev/business/nouns/template)): A Template is reusable Content with variables, filled from Things in the graph and authored as MDX, rendering a Message, Document, or Page.
  - **Theme** ([definition](https://startupbuilder.dev/business/nouns/theme)): A Theme is the design tokens of a Brand, its color, type, spacing, radius, and motion, that every Component reads when it renders.

## Defined here

  - **Business**: The genus of Startup: every Startup is a Business, and not every Business is one. A page says what holds for any Business first, then what the Startup layer adds.
  - **frame**: The page frame only: the `frame` field, `none`, `sheet` or `split`.
  - **ListSection**: The list a Component holds, such as the items of a feature grid.
  - **OfferTile**: One Offer drawn as a Tile: its name, price, lines and action. The `tiers` field of `pricing` holds them.
  - **rendering**: One output format of a record: HTML, JSON, Markdown, a share image or an email. Never an Interface.
  - **Section type**: One of the 27 layouts a section names in `block.type`, such as `hero` or `pricing`: the mdxui drawing of a Component.
  - **template package**: A set of packages styled for one look. Never a Template.
  - **Theme, as mdxui draws it**: The same Theme: a Brand's tokens plus its render policies, named by a Page in its `theme` field.
  - **Tile**: The root of every item a section lists, such as a feature or a plan. The payment credential keeps the startupbuilder.dev name.
  - **typeface**: A letterform family a Theme loads: display, text and mono.
  - **UsageGauge**: The display of usage against a limit. Billable usage keeps the startupbuilder.dev name.
  - **View**: An arrangement of Components bound to records. Dashboard extends View.

## Working terms

Working terms: mdxui-only words, each used in one meaning while the vocabulary settles.

  - **bound**: The most characters or items one field accepts.
  - **closed set**: The values one field accepts; any other value is refused.
  - **policy**: A render choice a Theme makes once, such as `dividers` or `featured`.
  - **preview**: A live render of a record on a docs page: an iframe of a file the build wrote. Maintainers call it a specimen.
  - **record**: A Page record: the JSON `PageSchema` parses. A record this site renders on every build is a living page.
  - **refusal**: The parse error that names a field past its bound, at its path.
  - **Slot**: A position a Template names for a section, such as the hero of a landing; slot rules are Spec. The App design has not settled what a slot is inside an App, so this name can change.
  - **role**: A named Theme token, such as `paper` or `accent`, that a Section type reads.
  - **section**: One entry of a Page's `sections`: a kind, a shell and one Section type.
  - **shell**: The fields that place and paint a section: `inset`, `density`, `surface`, `background`, `sticky` and `aside`.
  - **theme contract**: The roles and policies every Theme fills.
  - **worked Site**: A Site built here for one kind of Business: a worked example, not a customer.