Look up words
You can quickly look up the definition of a word or phrase while working in apps or browsing webpages.
Look up a word: Control-click the word or phrase (in some apps you may need to select it first), then choose Look Up from the shortcut menu. Or tap the word or phrase with three fingers (if the gesture is selected in Trackpad preferences).
If your trackpad supports force click, you can set the Look Up gesture to use that instead of a tap. (To force click, press firmly until you feel a deeper click.)
See the full definition: Click the “more” link at the end of the short definition.
See the word in the Dictionary app: Click Open in Dictionary.
See more information: Click a category—such as Knowledge or Movies—at the bottom of the Look Up window, or swipe left or right on the trackpad.
Add or customize dictionary sources: The dictionary definitions you see vary based on the sources available in Dictionary preferences. To add or customize sources, click Configure Dictionaries. In the Dictionary Preferences window, select or deselect sources. You can set options for a selected source, such as how to display pronunciations or which language of Wikipedia to search.
Tip: When Spotlight Suggestions are enabled, some apps—for example, Mail, Messages, and Notes—may outline an item (such as an artist name, a place, or a movie title) in text or make it a link as a hint that more information is available. Just click the arrow or the link to read more in the Look Up window. (Your messages, emails, and other content are not sent to Apple; only the items identified as Look Up hints and related usage data may be sent.)