A namespace is a unique identifier used in Salesforce to differentiate components, such as classes, triggers, and Visualforce pages, within managed packages. It ensures that the components you develop do not conflict with those from other packages or customizations in the subscriber's Salesforce org.

• Component Uniqueness: Prevents naming conflicts with components from other packages or custom code.

• Package Identification: Helps in identifying and managing the components of a specific package.

• Scope Management: Ensures that components within a package are encapsulated and do not interfere with other parts of the system.

• Required for Managed Packages: Necessary for creating managed packages, which are used to distribute applications on the AppExchange.