"For starters, GoldenDict supports a wide range of
dictionary formats, including StarDict dictionaries, Babylon .BGL
files, Dict dictionary files as well as ABBYY Lingvo source files
and audio archives. In addition to that, GoldenDict supports
MediaWiki-based references, which include both Wikipedia and
Wiktionary. But that's not all. Since GoldenDict is based on the
WebKit toolkit it can parse and display data from virtually any Web
site, so you can use GoldenDict to look up words in many popular
online references, as long as they support URL-based queries.
GoldenDict's other comfort creatures include Scan Popup and global
hotkeys. When the Scan Popup feature is enabled, GoldenDict pops up
a dictionary article for the currently selected word, and you can
use this functionality in any application."