Apt is not the Debian-linux package manager, it is an application for handheld devices running PalmOS 5.0+, such as the Palm T|X, Zire 22, Tungsten E2, all Treos, etc.
It is something of a mix between a preferences application, a button launcher and a macro program. The most distinguishing feature from other applications is that almost everything it does is on a per-application basis. The combination of per-application settings and arbitrary combination of events and responses leads to a tool that let's you customize control of your device to your heart's content.
An application on your device. Could be a system application like Calendar, or something you installed.
The application for which preferences are being set, selected by the pull-down list in the top center of Apt, initially labeled *Default*
Environmental preferences for a target app, like brightness, screen orientation, auto-off time or sound volume.
Things that happen while in the target application, like button presses, taps, card insertion, or simply time elapsed.
All the settings for a particular target (Prefs and Triggers) .
A control is a graphic element of a screen inside an app, like a button or a drop-down list. Apt can operate on some of the standard controls in your apps to simulate presses, etc.
A field is also a screen element in an app, but one where you can place a cursor and write data into.
Dynamic Input Area, also known as Virtual Graffiti. Refers to the area on the bottom of the screen on some devices, where you can write using graffiti characters. Devices with 480x320 resolution (like the Palm T3, T5, Lifedrive and T|X) have a DIA.
A series of actions that are sequenced together like in a program to perform some composite action. For example, "open Contacts, open the Category Drop-down, select the first category, tap the New button". In Apt, macros cannot be recorded, they have to be written manually.