I love using WordWeb on Windows. This free dictionary program is perfect! It hides away until it is invoked with the intuitive keyboard shortcut Ctrl + Alt + W. The WordWeb UI is simple and the dictionary database is comprehensive.
I wanted such a light, comprehensive and offline dictionary in Ubuntu. I was surprised to discover that the GNOME Dictionary, which is the default, uses online dictionary servers. This is painful since quick word lookup is really nice to have and I do not always have Internet access.
Here is how to turn GNOME Dictionary into an offline dictionary and configure it to use a English-English dictionary database:
Using the Synaptic Package Manager install the dictd package. dictd acts as the dictionary server and client dictionary programs, like GNOME Dictionary, can talk to it to get the definitions of words.
The dictd dictionary server may not be running after the package installation. Start it up by using the command:
$ sudo service dictd restart
Using the Synaptic Package Manager install the dict-gcide package. GCIDE is the GNU Collaborative International Dictionary of English. This contains entries from the Webster's Unabridged Dictionary, WordNet and other free sources. Webster's is the main source and it is quite dated, since it is the 1913 edition, which is now out of copyright and thus is available in the public domain.
You can now launch GNOME Dictionary in a jiffy by pressing Ctrl + Alt + W and lookup word definitions quickly without requiring any Internet access. 😊