
die App
app
An application program for a mobile device such as a smartphone or tablet, or for a computer.
Hast du eine gute App, um das Wetter zu prüfen?
Do you have a good app for checking the weather?
app
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app
An application program for a mobile device such as a smartphone or tablet, or for a computer.
Hast du eine gute App, um das Wetter zu prüfen?
Do you have a good app for checking the weather?
'App' is an English loanword and a short form of 'application' ('Anwendung' in German). It has become established in German as a common term for computer programs on mobile devices.
Ohne diese App könnte ich mein Handy kaum nutzen.
Without this app, I could hardly use my phone.
In everyday language, 'App' is often combined with certain verbs. You can 'herunterladen' (download), 'installieren' (install), 'öffnen' (open), 'nutzen' (use), or 'löschen' (delete) an app.
Ich muss die neue Version der App noch herunterladen.
I still need to download the new version of the app.
To describe the purpose of an app, German uses 'für' (for). To indicate where it is installed, German uses 'auf' (on).
Ich suche eine gute App für die Navigation in der Stadt.
I'm looking for a good app for navigation in the city.
program
Das Programm is a general term for software or a specific computer application. Die App refers especially to such an application on a smartphone, tablet, or computer and sounds more like a directly usable end-user product. Use App for mobile applications, and Programm for other software as well.

Für die gleiche Datenanalyse nutze ich unterwegs eine App auf meinem Tablet.
When I’m on the go, I use an app on my tablet for the same data analysis.
Für die Datenanalyse installierte ich ein neues Programm auf meinem Computer.
I installed a new program on my computer for data analysis.