Symbols

"Symbols.com contains more than 1,600 articles about 2,500 Western signs, arranged into 54 groups according to their graphic characteristics."

http://www.symbols.com/

Word Source

Online Dictionary and Thesaurus

http://word.sc/

e.g. http://word.sc/thes/word

The Skeptic's Dictionary

"The Skeptic's Dictionary is a website and a book. Each features definitions, arguments, and essays on occult topics ranging from acupuncture to zombies, and provides a lively, commonsense trove of detailed information on things supernatural, paranormal, and pseudoscientific."

http://skepdic.com/

Project Draw

http://draw.labs.autodesk.com/ADDraw/draw.html

DIA - A Drawing Program

"Dia is roughly inspired by the commercial Windows program 'Visio', though more geared towards informal diagrams for casual use. It can be used to draw many different kinds of diagrams. It currently has special objects to help draw entity relationship diagrams, UML diagrams, flowcharts, network diagrams, and many other diagrams. It is also possible to add support for new shapes by writing simple XML files, using a subset of SVG to draw the shape."

http://live.gnome.org/Dia

DIA for Windows : http://dia-installer.de/index_en.html

DIA Tutorial : http://www.seanet.com/~hgg9140/comp/diatut/all/all.html

DIA Charts and Diagrams : http://www.togaware.com/linux/survivor/DIA_Charts.html