# Definition and type definition

In IntelliJ IDEA, you can see where and how symbols, such as classes, fields, methods, functions, or tags    are defined in your project. For this purpose, the IDE features the Quick Definition popup.

![Quick Definition popup](https://resources.jetbrains.com.cn/help/img/idea/2026.2/quickDefinitionLookup.png)

Procedure: View definition of a symbol at caret

* Place the caret at a symbol in the editor and press `Ctrl+Shift+I` (Windows), `⌥ Space` (macOS), `⌘ ⇧ I` (IntelliJ IDEA Classic (macOS)), `⌘ Y` (macOS System Shortcuts), `Ctrl+Shift+I` (XWin), `Ctrl+Shift+I` (GNOME), `Ctrl+Shift+I` (KDE), `Ctrl+Shift+I` (Emacs), `Ctrl+Shift+I` (Sublime Text), `⌥ Space` (Sublime Text (macOS)), `Ctrl+Shift+I` (NetBeans), `Alt+F12` (Visual Studio), `⌥ Space` (Visual Studio (macOS)), `Ctrl+Shift+I` (Eclipse), `⌥ Space` (Eclipse (macOS)) (or click `View | Quick Definition` in the main menu). You can also   press `Ctrl+Shift+A` (Windows), `⌘ ⇧ A` (macOS), `⌘ ⇧ A` (IntelliJ IDEA Classic (macOS)), `⌘ ⇧ P` (macOS System Shortcuts), `Ctrl+Shift+A` (XWin), `Ctrl+Shift+A` (GNOME), `Ctrl+Shift+A` (KDE), `Escape, X` (Emacs), `Ctrl+Shift+P` (Sublime Text), `⌘ ⇧ P` (Sublime Text (macOS)), `Ctrl+I` (NetBeans), `Ctrl+Shift+A` (Visual Studio), `⌘ ⇧ A` (Visual Studio (macOS)), `Ctrl+Shift+A` (Eclipse), `⌘ 3` (Eclipse (macOS)), start typing `Quick Definition` , then select the action from the list.

* Alternatively, with the `Ctrl` (Windows), `Ctrl` (macOS), `Ctrl` (IntelliJ IDEA Classic (macOS)), `Ctrl` (macOS System Shortcuts), `Ctrl` (XWin), `Ctrl` (GNOME), `Ctrl` (KDE), `Ctrl` (Emacs), `Ctrl` (Sublime Text), `Ctrl` (Sublime Text (macOS)), `Ctrl` (NetBeans), `Ctrl` (Visual Studio), `Ctrl` (Visual Studio (macOS)), `Ctrl` (Eclipse), `Ctrl` (Eclipse (macOS)) key pressed, hover over any symbol. IntelliJ IDEA displays the symbol as a link and shows its definition in a tooltip. Click this link to jump to the definition of the symbol.

![View definition in a tooltip](https://resources.jetbrains.com.cn/help/img/idea/2026.2/view-definition.animated.gif)

You can open a definition in the Find tool window. To do so, click the ![Options](https://resources.jetbrains.com.cn/help/img/idea/2026.2/app.actions.more.svg) icon in the top-right corner of the popup and click ![Open in Find tool window](https://resources.jetbrains.com.cn/help/img/idea/2026.2/app.actions.moveToBottomLeft.svg) Open in Find Tool Window.

To open the source code of the definition for editing and close the popup, click the ![Options](https://resources.jetbrains.com.cn/help/img/idea/2026.2/app-client.expui.general.moreVertical.svg) icon and then click ![Edit](https://resources.jetbrains.com.cn/help/img/idea/2026.2/app.expui.general.edit.svg) Edit Source (`F4` (Windows), `⌘ ↓` (macOS), `F4` (IntelliJ IDEA Classic (macOS)), `F4` (macOS System Shortcuts), `F4` (XWin), `F4` (GNOME), `F4` (KDE), `F4` (Emacs), `F4` (Sublime Text), `F4` (Sublime Text (macOS)), `F4` (NetBeans), `F4` (Visual Studio), `⌘ ↓` (Visual Studio (macOS)), `F12` (Eclipse), `F3` (Eclipse (macOS))).

> **Tip:**
> For markup languages, IntelliJ IDEA retrieves definitions of symbols from the specified DTD or schema.  For more information, refer to [HTML](editing-html-files.html) and [XML](working-with-xml.html).

## Type definitions

The Quick Type Definition feature allows you to view the type definition of variables, fields,  methods, or any other symbols in a popup without switching from the code you're editing.

Procedure:

* Place the caret at the symbol for which you want to view the type definition and select `View | Quick Type Definition`.

![Viewing type definition in a popup](https://resources.jetbrains.com.cn/help/img/idea/2026.2/ij-quick-type-definition.png)

To open the source code of the definition for editing and close the popup, click the ![Options](https://resources.jetbrains.com.cn/help/img/idea/2026.2/app.actions.more.svg) icon and then click ![Edit](https://resources.jetbrains.com.cn/help/img/idea/2026.2/app-client.expui.general.edit.svg) Edit Source (`F4` (Windows), `⌘ ↓` (macOS), `F4` (IntelliJ IDEA Classic (macOS)), `F4` (macOS System Shortcuts), `F4` (XWin), `F4` (GNOME), `F4` (KDE), `F4` (Emacs), `F4` (Sublime Text), `F4` (Sublime Text (macOS)), `F4` (NetBeans), `F4` (Visual Studio), `⌘ ↓` (Visual Studio (macOS)), `F12` (Eclipse), `F3` (Eclipse (macOS))).

IntelliJ IDEA doesn't have a default keyboard shortcut for this action, but you can manually configure it in the settings. For more information about configuring custom shortcuts, refer to [Configure keyboard shortcuts](configuring-keyboard-and-mouse-shortcuts.html).