Words can be entered in the search bar by just typing the first few letters. The application will perform an incremental search to show any matching headwords or forms and will try to bypass spelling errors. Clicking on any word in a definition searches for that word in the dictionary again. Almost any word is clickable, except the pronunciations in phonetic characters and numerals. The Preferences allow a user to select from three different pronunciation schemes, either US English, or British English. The dictionary and thesaurus in Dictionary are in an XML format, but make use of precompiled binary index files to access the XML file directly. Therefore, the lexicon cannot easily be modified. However, the user can add new words to the macOS system-wide spell checker, which uses its own lexicon.
Quick access
In applications which support "Services", there is an option in the application menu which brings up the Dictionary application and displays the definition of a selected word. The same option appears in the contextual menu after a Control-click on the selected word.
As of Mac OS X Lion, a three finger tap on the trackpad has the same effect as the Control Command D shortcut.
In applications which support the ability of the user to drag selected text, it is possible to select a word and drop it onto the icon of the Dictionary application in the Dock.
Dashboard includes a widget for accessing the Dictionary application.
macOS catches any queries to the dict:/// URI scheme, say from a web browser, and routes them back to the Dictionary application.
Since OS X Leopard, the dictionary has become tightly integrated with Spotlight, allowing users to view definitions from immediately within the system search.
Other languages
added the Japanese-language dictionary Daijisen, Progressive English to Japanese and Progressive Japanese to English dictionaries, and the 25,000-entry thesaurus "Tsukaikata no Wakaru Ruigo Reikai Jiten", all of which are provided by the Japanese publisher Shogakukan. The Japanese dictionaries do not show up by default and must be enabled in Preferences. In OS X 10.8 Mountain Lion, the Japanese dictionaries were replaced by Super Daijirin and the Wisdom English-Japanese Dictionary. In addition, dictionaries were also added for French, German, Spanish, and Chinese. Software such as DictUnifier can be used to add more dictionaries to the application.
Criticism
Although dictionary entries purport to be neutral, some entries in the Apple Dictionary application have been criticized for exhibiting various forms of bias. A complaint was filed in 2013 about the entry for "gay," which included the "informal" definition "foolish, stupid, or unimpressive: making students wait for the light is kind of a gay rule." The definition has since been amended with the label "offensive." In addition, writers of the dictionary exhibit gender bias in definitions such as "political," and "apolitical." The definition for "political" associates the word with a man, " he's a political man" and the example for "apolitical" associates the word with a woman, "not interested or involved in politics: a former apolitical housewife." This form of gender bias has been documented in many dictionaries.
