app

Etymology 1

Shortening of application.

noun

1. (computing, mobile telephony) An application (program), especially a small one designed for a mobile device.
   A visual tool can be thought of as a graphics app that generates most of your program's GUI code for you 1999 February, Maximum PC, volume 4, number 2
   So is a spreadsheet app, but I'm not going to put those on a web site any time soon. 1999, Jerry Bradenbaugh, JavaScript application cookbook, page xi
   The Web browser was the killer app that kickstarted the Internet and, in turn, enabled it to be embedded in everything 1999 November, AUUGN, volume 20, number 4, page 9
   Want realtime flight and gate updates? A calorie counter? A remote for your DVD player? Chances are there's an app for it. Smartphones separate themselves in another key area: connectivity 2005 May, Popular Science, volume 266, number 5, page 78
2. (military) application (use, purpose; not a computer program)
   SCULLY: What are these chips used for? PENDRELL: Video games, brake systems, they're finding new apps every day. I just read about one being designed to help the severely disabled operate computers using brainwaves. 1995, The X-Files (TV series), Nisei (episode)
3. (education, informal) application (to a college etc.)
   “Ky—please don't take this the wrong way—I actually have to wear a dress from our line. You know, to show off my marketing materials on my college app. So, I'm working on it with Hannah.” 2011, Nicole Leigh Shepherd, Stealing Bases

Etymology 2

Shortening of appetizer.

noun

1. (informal) appetizer
   The food is some of Breck's best: apps like sweet potato gnocchi with smoked chicken and sage cream[…] 2007, Evelyn Spence, Explorer's Guide Colorado's Classic Mountain Towns
   If you lay out a platter of these exciting, beautiful vegetarian appetizers, the other apps will pale in comparison. 2009, Robin Asbell, New Vegetarian
   This is not to say that we only serve apps at dinner parties. Quite the contrary; but for smaller gatherings, good appetizers can distinguish you as a host who puts more thought and effort into his or her party menu. Better yet, most apps are relatively easy to make[…] 2010, Bill Allen, Grillin', Chillin', and Swillin', page 1

Etymology 3

Shortening of appearance.

noun

1. (sports) An appearance in a game.
   That player has had ten apps this season.