Definition: '.env.app.conf' in programming refers to a configuration file used for environment variables, including the name of an application that manages these variables (the 'app'). This file typically contains data related to the app's configuration, such as settings like database connections, authentication mechanisms, or server configurations, which can be accessed and modified from anywhere within the app. The .env.app.conf file is crucial for applications where application-specific configuration is needed at runtime, enabling developers to customize these variables without altering the underlying software code.