| Ability | An abstraction of a functionality that an application can provide. It is the minimum unit for the system to schedule the application. An application can contain one or more **Ability** instances.|
| FA | Feature Ability, an ability that provides a UI for user interaction in the ability framework of the FA model. The FA supports only the Page ability template.|
| PA | Particle Ability, an ability that does not have a UI in the ability framework of the FA model. It provides services and support for FAs. For example, a PA can function as a background service to provide computing power or as a data store to provide data access capabilities. The PA supports three types of templates: Service, Data, and Form ability templates.|
| FA model | One of the two ability framework models. The FA model applies to application development using API version 8 and earlier versions. The FA model provides FAs and PAs. The FA supports the Page ability template, and the PA supports the Service, Data, and Form ability templates. For details, see [FA Model Overview](../../application-dev/ability/fa-brief.md).|
| FA model | One of the two ability framework models. The FA model applies to application development using API version 8 and earlier versions. The FA model provides FAs and PAs. The FA supports the Page ability template, and the PA supports the Service, Data, and Form ability templates. For details, see [FA Model Overview](../../application-dev/ability-deprecated/fa-brief.md).|
| Stage model| One of the two ability framework models. The stage model applies to application development using API version 9 and later versions. The stage model provides abilities and Extension abilities. The latter ones are extended to Service Extension abilities, Form Extension abilities, Data Share Extension abilities, and more.|
