iOS 5 is Apple's fifth mobile operating system, released on Oct 13, 2011. It runs on iPhone 3GS, iPhone 4, iPhone 4S, iPod Touch 3rd and 4th generation, as well as all iPad models. It was succeeded by iOS 6.

An Android emulator is software which simulates the functionality of an Android device running the Android OS. Emulator allows developers to develop and test applications without the need of various real devices with different configurations.

WebDriver is an API for controlling web browsers, imitating a real user. It's mostly used for automated tests. WebDriver has multiple language bindings and drivers (allowing to control various browsers). If your question is specific to one of them, make sure to also include the appropriate tag.

The user-facing part of an application. In a desktop application this would include the windowing framework and the forms the user interacts with; in a command line program it would be the available commands and arguments; and in a web app it would refer to the HTML and JavaScript.

Garbage collection (GC) is a form of automatic memory management which attempts to reclaim garbage, or memory occupied by objects that are no longer in use by the program.

XMLHttpRequest (XHR) is a JavaScript object that exposes an API for making asynchronous HTTP requests from frontend code running a Web browser — that is, for enabling the programming technique known as AJAX. The XHR API is a legacy API. It has been superseded by the Fetch API.

The Java Virtual Machine (JVM) enables a set of computer software programs and data structures to use a virtual machine model for the execution of other computer programs and scripts. Use this tag for questions dealing with tools provided by a JVM or how it works in a specific scenario.

A rotation is a circular movement of an object around a center (or point) of rotation. On a mobile device, it indicates the change of orientation.

Canvas is an HTML element that allows for dynamic, scriptable rendering of 2D shapes, 3D shapes, bitmap images and animations in both 2D and 3D.

A graphical user interface element that allows the user to select one or more items from a list.

A time zone is a region on Earth that has a uniform, legally mandated standard time. It is often represented by an identifier, such as "America/Los_Angeles". Do not mistake an offset such as -07:00 as a time zone. A time zone is much more than that. Please read the entire tag wiki for details.