GEM ( https://en.m.wikipedia.org/wiki/GEM_(desktop_environment) ) treated files with the .APP extension as programs.

“App” is the obvious abbreviation of application, I think the iPhone sort of publicized it, but I’ve always used phrases like “spinning up a new app” even with things like Delphi in the 90s

Calling computer programs "applications" is a neologism. Once that catches, shortening to "apps" is automatic and happens everywhere at once, somewhat the way programs became "proggies" in places.

Some of us are still cheesed at having our old, comfortable programs re-branded to dodgy new applications:

"Programs run, applications crash."

“Applications” doesn’t seem to be particularly new to me: e.g., Rapid Application Development (RAD) tools like Delphi and Visual Basic were fairly popular in the 90s. And, the jargon file attests to the use of the term to signify programs for non-developers going as far back as 90: http://www.catb.org/jargon/oldversions/jarg211.txt

The suits tried to get people calling what they sold "applications" right from the beginning. "Nobody will pay for a program, but they will pay anything for an application." Back then, an application was, literally, what you were using the computer to get done: a spreadsheet would be a program, budgeting an application. The suits bought and sold "applications"; users ran programs.

Then Eternal September happened, there were too few to push back, and all the other stuff paying customers used to demand--training, printed manuals, not crashing all the damn time--fell away, and finally the program became, itself, the whole application.

Then the users needed an abbreviation for what it was that was crashing: the "app".

In the 80's, I wasted far too much time writing PROGRESS 4GL "Applications", which was 4GL code applied to a particular database ..

This version of the jargon file from 1990 has an entry for “app”

http://www.catb.org/jargon/oldversions/jarg211.txt

Wiktionary has a cite for the phrase “killer app” in ‘99

https://en.m.wiktionary.org/wiki/app

iOS .app was inherited from OS X .app which was inherited from NeXTStep .app, circa 1988.

fun thing: executable application folders like in OSX were a RiscOS thing.

And a NeXT thing.

And the original Mac had a very similar concept with a single file that had an embedded resource fork. And even DOS applications were very often distributed as single folders with all the application files in them, you just needed to run the actual binary manually.

The idea that one-object = one-application is at least as old as desktop computing itself because it fits seamlessly into the file/folder metaphor. Sadly, modern desktops have largely degraded in this regard.

Well, on MacOS they come straight from NeXT so it's no big deal. But what's interesting is that they were on other systems in the 80s too - whereas in the 2000s they were one of the things that made people say MacOS is better than anything else, since only they have these special folders.

We used the term in Newton, circa 1991.

... and a peer here mentions that the term existed in GEM as well. I worked on that a bit, too. Guess I forgot :-)