# Application Package Glossary ## E ### ExtensionAbility A component that provides extension abilities for specific scenarios (such as service widgets and input methods) in the stage model. ## F ### FA Feature Ability, an ability with a UI to interact with users in the FA model. ### FA model It is the only application development model supported by API version 8 and earlier. Now, the stage model is recommended for application development. ## H ### HAP Harmony Ability Package, released with the file name extension .hap, contains all content of an application, including code, resources, third-party libraries, and an application configuration file. ### HAR HarmonyOS Archive, released with the file name extension .har, is a static shared package and can be reused in the compilation state. It can contain code, C++ libraries, resources, and configuration files, and is used to share code and resources. ### HSP Harmony Shared Package, released with the file name extension .hsp, is a dynamic shared package and can be reused during runtime. It can contain code, C++ libraries, resources, and configuration files, and is used to share code and resources. ## M ### Module A module is a part of an application. Each module has an independent module.json5 configuration file. In a project, Entry, Feature, HSP, and HAR are application modules. ## P ### PA Particle Ability, an ability without a UI in the FA model. PAs are invoked to implement FA functionalities. For example, a PA runs in the background to provide the computing capability or acts as a data warehouse to provide the data access capability. ## S ### Stage model Application model available since API version 9. It provides two types of application components: UIAbility and ExtensionAbility. In this model, classes such as **AbilityStage** and **WindowStage** are provided as the stage of application components and windows. That's why it is named stage model. ## U ### UIAbility A component in the stage model used to provide UI capabilities for user interaction. ## X ### System-level HSP An HSP preset in the system by the OEM. As the underlying implementation of Kits, it is indirectly depended on by third-party applications and runs in the third-party process space.