> ## Documentation Index
> Fetch the complete documentation index at: https://docs.arinnaos.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Core Concepts

> Understand the key concepts used throughout ArinnaOS.

# Core Concepts

## Organisation

An organisation is a tenant workspace in ArinnaOS.

Each travel business operates inside its own organisation.

## User

Users access ArinnaOS by invitation.

## Membership

A membership connects a user to an organisation.

## Roles and permissions

Roles group permissions. Permissions control what users can do.

## Supplier

A supplier is the parent record for hotels, transport providers, guides, restaurants, and other service providers.

## Tour template

A reusable product structure without operating dates.

## Departure

A scheduled operation linked to a specific tour template version.

## Passenger

A reusable traveller profile.

## Tour passenger

A passenger participating in a specific departure.

## Quote

A commercial proposal.

## Booking

A commercial contract created explicitly from an accepted quote.

## Invoice and payment

Invoices request payment. Payments record money received.