Lookup is a search interface to electronic dictionaries within Emacs.
You can use various sources (such as CD-ROM books, dictionary server on
the network, and so on) as dictionaries by the simple operation.

Lookup works on GNU Emacs 19.28 or later, XEmacs 20.3 or later, Mule
2.3, and Meadow 1.0 or later.

WWW: http://openlab.ring.gr.jp/edict/lookup/index.html