The original edict.el was written by Per Hammarlund. It is an interface
to the EDICT Japanese-English dictionary compiled by Jim Breen at
Monash University. Using the region and a couple of keystrokes,
edict.el looks up the Japanese key and returns all the EDICT entries
containing that key in a pop-up buffer. English is even easier: you
just point anywhere in the word you want to look up.

Bob Kerns added a morphology engine, which reduces a highly inflected
Japanese word to a list of dictionary forms (for example itta -> (iku,
iu)), all of which are looked up.