Look up a word on your Mac,
including where the shortcut fails.

Aug 13, 2026 · 2 min read

macOS already has a lookup. Select a word and press ⌃⌘D, or tap it with three fingers. It is fast, it is free, and you should use it. It also only works in apps built on Apple's own text views, hands you a monolingual definition by default, and forgets the word the moment the panel closes.

Control Command D, and the three finger tap

Select a word and press ⌃⌘D. You can skip the selecting and just hover the pointer over it. A small panel opens with the definition, a thesaurus entry and a Wikipedia summary if there is one.

On a trackpad, tapping a word with three fingers does the same. If nothing happens, open System Settings, then Trackpad, then Look up and data detectors, and choose between the three finger tap and a force click.

To get more than the English dictionary, open the Dictionary app, go to Dictionary then Settings, and tick the languages you want. Drag them up the list to decide which one answers first.

If you need to find where a word appears rather than learn what it means, that is a different task. Use finding a word on Mac instead.

Why it sometimes does nothing at all

The shortcut needs a real macOS text view. Slack, Discord, Notion, VS Code and most other apps built on web technology do not give it one. Neither do in browser PDF viewers, video players, images or remote desktop windows.

There is also the language problem. If you are reading something in a language you are learning, an English to English definition is often not the help you needed, and switching dictionaries mid paragraph gets old fast.

Then there is the forgetting. The panel closes and there is no record you ever looked at the word. Three days later you meet it again and it is new again.

Look up what is on the screen instead

Press ⌥A and box the word. macOS text recognition reads that patch of screen, and the word is looked up in the sense the sentence around it is using, not as a list of every meaning it has ever had.

Because it reads pixels, the apps in the paragraph above stop being special cases. A PDF that will not select, a subtitle, a screenshot, an error dialog. All the same.

The part the built in dictionary skips

Every word you look up is saved with the sentence it came from, in a searchable library that stays on your Mac. That pairing is the whole point: a word on its own is trivia, a word carrying the line you first hit it in has somewhere to live.

From there it exports to Anki, CSV, Excel, JSON or PDF, with the card layout picked and previewed before the file is written.

Where the text goes

Your library lives on your Mac. No account, no sync server, no ads. The picture is read on your machine and never leaves it, so nothing gets uploaded to a website.

The text you scan does go out to an AI so it can explain the word as your sentence uses it, with nothing attached that says who you are. The privacy page spells out exactly what is sent and what is kept.

Why the word does not stick around

You looked it up, understood it, and three days later it was a new word again. The built in panel keeps no record of any of it. It went because you kept the definition and threw away the sentence it was wrapped in.

A word on its own is a list of definitions. Run does not mean the same thing in every sentence, so a dictionary hands you fifty meanings and leaves you guessing which one this one was. That word inside a sentence is the one you needed, with a situation attached. Without that situation, your brain has nothing to hook it to. You get the dictionary's answer instead of yours.

Save the sentence alongside the word. When it comes back you get your own sense of it, with the paragraph it arrived in still attached. The pairing is the whole point. Review from the sentence, not just the word, because that is how you encounter it in real life. If you already use Anki, export your vocabulary words with their sentences and build cards around them. A month of reading turned into a searchable library is something you will actually open.

LeafyApp does this with one keystroke. Everything you look up lands in a library that stays on your Mac and exports to Anki, CSV, Excel, JSON or PDF whenever you want it elsewhere.