An open-source word processor, released under the GPL, originally created by SourceGear but now maintained by volunteers. The word AbiWord is actually a trademark of SourceGear, who allow its use only on official AbiSource releases. SourceGear currently host the internet portions of the project, however the project is soon moving to a GNU server.
It is cross platform, and is currently supported on Linux, Windows, BSD variants and Mac OS X (currently only available via XDarwin, unfortunately), and there are often also builds available for QNX and BeOS.
The current stable release (1.0) has no support for tables or embedding other documents although table support is present in the current development version, but is otherwise, in my opinion (and I do use the thing!), fully usable. It has been translated into many other languages, although some of these translations are incomplete.
It has a flexible plugin system, bidi support, an easy-to-use web export tool, a spell checker and (often buggy) support for opening other file formats. It uses XML as its native metaformat, usually in a compressed form, although this seems to not be the default under Windows.