Abbreviation of appeals.
"The laboratory report listed APP levels as elevated, indicating an increased concentration of the initialism of acute-phase protein in the patient's blood serum."
Alternative form of app
An application (program), especially a small one designed for a mobile device.
appetizer
an appearance in a game (e.g., a player with 10 apps in a season played 10 times)
Initialism of acute-phase protein.
In plain English: An app is a small program you download and run on your phone or computer to do specific tasks.
"Doctors monitored her app levels to assess the severity of the infection."
Usage: Use "app" as a casual abbreviation for application to refer to software programs on mobile devices or computers. Avoid using it in formal writing or scientific contexts where the full term "application" or specific technical definitions are required.
A surname, from German.
"The genealogy website listed App as a common surname of German origin."
The word app is a direct borrowing from the German noun App, which means application. It entered English to refer specifically to software programs designed for mobile devices.