diff --git a/index.d.ts b/index.d.ts
index 9a75420..690e169 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -67,6 +67,7 @@ declare namespace contextMenu {
 		readonly saveImage: (options: ActionOptions) => MenuItem;
 		readonly saveImageAs: (options: ActionOptions) => MenuItem;
 		readonly copyImageAddress: (options: ActionOptions) => MenuItem;
+		readonly lookUpSelection: (options: ActionOptions) => MenuItem;
 	}
 
 	interface Options {
@@ -115,6 +116,13 @@ declare namespace contextMenu {
 		*/
 		readonly showInspectElement?: boolean;
 
+		/**
+		Show the `Look Up [selection]` menu item when right-clicking text on macOS.
+
+		@default true
+		*/
+		readonly showLookUpSelection?: boolean;
+
 		/**
 		Overwrite labels for the default menu items. Useful for i18n.
 
diff --git a/index.js b/index.js
index c0fa678..d0a6b9a 100644
--- a/index.js
+++ b/index.js
@@ -1,5 +1,6 @@
 'use strict';
 const electron = require('electron');
+const cliTruncate = require('cli-truncate');
 const {download} = require('electron-dl');
 const isDev = require('electron-is-dev');
 
@@ -126,10 +127,22 @@ const create = (win, options) => {
 						text: props.srcURL
 					});
 				}
+			}),
+			lookUpSelection: decorateMenuItem({
+				id: 'lookUpWord',
+				label: `Look Up “${cliTruncate(props.selectionText.trim(), 25)}”`,
+				visible: process.platform === 'darwin' && hasText,
+				click() {
+					if (process.platform === 'darwin') {
+						webContents(win).showDefinitionForSelection();
+					}
+				}
 			})
 		};
 
 		let menuTemplate = [
+			defaultActions.separator(),
+			options.showLookUpSelection !== false && defaultActions.lookUpSelection(),
 			defaultActions.separator(),
 			defaultActions.cut(),
 			defaultActions.copy(),
diff --git a/package.json b/package.json
index 04f9e52..53d0417 100644
--- a/package.json
+++ b/package.json
@@ -28,6 +28,7 @@
 		"image"
 	],
 	"dependencies": {
+		"cli-truncate": "^1.1.0",
 		"electron-dl": "^1.2.0",
 		"electron-is-dev": "^1.0.1"
 	},
diff --git a/readme.md b/readme.md
index fadba9d..76c88de 100644
--- a/readme.md
+++ b/readme.md
@@ -93,6 +93,13 @@ Default: [Only in development](https://github.com/sindresorhus/electron-is-dev)
 
 Force enable or disable the `Inspect Element` menu item.
 
+#### showLookUpSelection
+
+Type: `boolean`<br>
+Default: `true`
+
+Show the `Look Up [selection]` menu item when right-clicking text on macOS.
+
 #### labels
 
 Type: `Object`<br>