[ja2ke]

They've always been at least "Applications" on the Mac, which is probably where the NeXTSTEP team got the file extension. On DOS/Windows it was and still is "Executable," though people are starting to casually use "App" everywhere.

[Samuel_Michon]

Yes, Macintosh software programs were always in the 'Applications' folder. However, we never called them 'apps'. Classic MacOS didn't use file extensions, programs had a 'type code', 'APPL' (ResEdit allowed you to view those codes and edit the resources within an application). At the time, when we used a short word for software programs, we'd call them 'progs'. This changed when Apple acquired NeXT. The Yellow Box software programs in Rhapsody were the first ones I saw that had .app file extensions, and when I went to a preview of that next gen OS in 1997, Steve Jobs repeatedly called them 'apps'.