Dict: Display Word Definitions from RFC2229 Dictionary Servers

Dict is currently available from its Git repository. To clone the latest version, run:

git clone git://git.eshelyaron.com/dict.git

Then use M-x package-install-file to install dict.el from the cloned repository as a package.

Dict defines a single autoloaded command for displaying word definitions:

Command: dict-describe-word

Prompt for a word and display its definition.

This command prompts for a word in the minibuffer, obtains its definition from a dictionary server, and displays it in a *Help* buffer. (See Help in the Emacs manual.)

dict-describe-word uses dictionary matches for the word at point, if any, as the minibuffer’s “future history” (see Minibuffer History). This means that you can display the definition of the word at point by typing M-x dict-describe-word RET RET.

Dictionary servers usually support several dictionaries that you can query. When Dict asks the dictionary server for a word definition, it needs to specify in which dictionary the server should look. The dictionary Dict uses is determined by the user option dict-dictionary. By default this is set to nil, which says to prompt for a supported dictionary the first time you invoke dict-describe-word.

Similarly, the user option dict-strategy specifies a dictionary matching strategy for finding completion candidates. This is set to nil by default, like dict-dictionary, which means that dict-describe-word prompts also for a supported matching strategy the first time you use it.

You can customize dict-dictionary and dict-strategy to appropriate values before calling dict-describe-word to inhibit these prompts on first use. (Also see Customizing Dict for more customization options.)

The following user options affect the behavior of dict-describe-word:

User Option: dict-server-host

Host name or IP address of the dictionary server to use. Defaults to nil, which means to first try “localhost”, and if no local server is available then fallback to the host specified by dict-default-server-host.

User Option: dict-default-server-host

Remote dictionary server to use when there is no local server and dict-server-host is nil. Defaults to “dict.org”.

User Option: dict-server-port

Port number to use for connecting to the dictionary server. Defaults to 2628.

User Option: dict-dictionary

Name of the dictionary to query, which must be supported by the dictionary server. Default to nil, which means to prompt for a supported dictionary on the first invocation of dict-describe-word.

User Option: dict-dictionary-prompt

Prompt string to use when prompting for a dictionary. Defaults to “Set dictionary”.

User Option: dict-strategy

Name of the dictionary matching strategy to use, which must be supported by the dictionary server. Default to nil, which means to prompt for a supported strategy on the first invocation of dict-describe-word.

User Option: dict-strategy-prompt

Prompt string to use when prompting for a matching strategy. Defaults to “Set matching strategy”.

User Option: dict-process-name

Name to use for the dictionary server connection process. Defaults to “dict”.

User Option: dict-process-buffer-name

Name of the buffer to use for the dictionary server connection process output. Defaults to “*​dict output*”.

User Option: dict-display-definition-function

Function to use for displaying word definitions. The function must take two string arguments, the word and its definition, and display the definition to the user. Defaults to the function dict-display-definition-in-help-buffer, which displays the definition in a *Help* buffer.

Dict provides the following functions for querying dictionary servers from Elisp:

Function: dict-match-word word

Return a list of dictionary matches for WORD.

Function: dict-define-word word

Return the dictionary definition of WORD, or nil if not defined.

The function dict-match-word queries the dictionary server for words that match a given input in the dictionary specified by the user option dict-dictionary, based on the matching strategy specified by the dict-strategy. Similarly, dict-define-word retrieves and returns the definition of a given word in the dictionary specified by dict-dictionary as a string, or it returns nil if the dictionary server doesn’t find a definition for that word.

The best way to extend Dict with bespoke commands for your workflow, is to define wrappers around dict-describe-word that supply specific words or locally bind some user options to specific values. For example, the following command looks up the definition of the word at point in the WordNet dictionary without prompting:

(defun my/wordnet-definition-for-word-at-point (word)
  (interactive (list (word-at-point)))
  (let ((dict-dictionary "wn"))
    (dict-describe-word word)))

To create a command that displays definitions in the echo area (see Echo Area), locally bind dict-display-definition-function to an appropriate function:

(defun my/echo-word-definition (word)
  (interactive (list (dict-read-word)))
  (let ((dict-display-definition-function
         (lambda (_word definition)
           (message definition))))
    (dict-describe-word word)))

Note the use of the function dict-read-word in the above definition. This helper function prompts for a word defined in dictionary, with completion, using the word at point as the minibuffer’s “future history”. This is also what dict-describe-word uses to prompt for a word when you call it interactively.

Here’s an example configuration for Dict:

(with-eval-after-load 'dict
  ;; some settings
  (setq dict-server-host "dict.org"
        dict-dictionary  "gcide"
        dict-strategy    "prefix"))

(keymap-global-set "M-#" #'dict-describe-word)

If you install Dict as a package then dict-describe-word is autoloaded on demand, so there’s no need to require anything before you use it.

The main motivation behind the development of Dict was to resolve some issues that the author came across with the dictionary.el package that ships with Emacs. This package, initially written by Torsten Hilbrich to support both GNU Emacs and XEmacs, was added as a library to Emacs core in version 28.

In their essence, Dict and dictionary.el have similar goals and they both operate in a similar manner–getting word definitions from RFC2229 servers, and displaying them in an Emacs buffer.

Dict’s differentiation comes from its simplicity and extensibility–while dictionary.el defines a bespoke major mode and interface for browsing word definitions, Dict leverages Emacs’s Help mode by default, and lets you extend and control every aspect of its behavior via customization options.

dict.el is also shorter than dictionary.el–just under 300 lines of code!