Dictionary.Merrian-com:http://dictionary.reference.com/
Merriam-Webster OnLine:http://www.m-w.com/
Cambridge dictionaries online:http://dictionary.cambridge.org/
Your dictionary com:http://www.yourdictionary.com/

Taiwanese dictionaryhttp://daiwanway.dynip.com/cgi/tdict.acgi
Dr.eye:http://www.dreye.com:8080/axis/ddict.jsp?w=&dod=0102&ver=big5
Yahoo dictionary:http://tw.dictionary.yahoo.com/
Thecus:http://www.onlinedict.com/