快捷键，又叫快速键、组合键或热键，指通过某些特定的按键、按键顺序或按键组合来完成一个操作，很多快捷键往往与如Ctrl键、Shift键、Alt键、Fn键以及Windows平台下的Win键和Mac机上的Cmd键（曾有Meta键）等配合使用。各种控件上一般可以通过Alt组合键访问的的访问键。快捷键的有效范围不一定相同，比如：系统级快捷键可以全局响应，不论当前焦点在哪里、运行什幺进程，按下时都能起作用；而应用进程级热键只能在当前活动的进程中起作用，当应用进程热键的定义进程不活动或在后台运行时，热键就无效了；控件级的热键则仅在当前控件中起作用。

In computing, a keyboard shortcut is a series of one or several keys that invoke a software or operating system operation (in other words, cause an event) when triggered by the user. The meaning of term "keyboard shortcut" can vary depending on software manufacturer. For instance, Microsoft differentiates keyboard shortcuts from hotkeys ("mnemonics" on Windows) whereby the former consists of a specific key combination used to trigger an action, and the latter represents a designated letter in a menu command or toolbar button that when pressed together with the Alt key, activates such command—whereas a "hotkey" on Windows is a system wide shortcut that is always available in all contexts as long as the program responsible for it is running and not suspended.