You’re probably used to Mac apps using red underlines to mark misspelled words, but did you know that macOS has long included a fully featured Dictionary app as well? It provides quick access to definitions and synonyms in the New Oxford American Dictionary and the Oxford American Writer’s Thesaurus, along with definitions of Apple-specific words like AppleCare and MacTCP. But that’s far from all it can do.
First, let’s make sure we’re all on the same page. Launch the Dictionary app from your Applications folder and then type a word or phrase into the Search field. As you type, Dictionary starts looking up words that match what you’ve typed so far—you don’t even have to press Return. If more than one word matches what you’ve typed, click the desired word in the sidebar.
Notice the lozenges below the toolbar, representing the references that Dictionary can consult, and no, your eyes aren’t deceiving you—Dictionary can look things up in Wikipedia if your Mac has an Internet connection. In short, Dictionary gives you instant access to a dictionary, a thesaurus, and an encyclopedia containing over 5.4 million articles in English alone! You can click a reference’s lozenge to limit your search, or select All to scan all of them.