"App" significantly predates the iPhone. Binary/warez sites regularly used "apps" as a shorthand, NeXTSTEP used .app before Apple bought it...heck, Apple called an early Mac development framework "MacApp".
We've been calling applications "apps" for going on thirty years at a minimum.
Mobiles pre-smartphone boasted of their 'Java App Library', too. I don't know anyone who used one deliberately though, with the slow and extortionately priced data of the time.
We've been calling applications "apps" for going on thirty years at a minimum.