國語辭典
國語辭典由台灣教育部國語推行委員會所編錄。 此辭典所收錄的詞彙,除一般之單音節詞、雙音節詞外,另收有成語、慣用語、歇後語、準固定語、諺語、 外來語和專門用語。
URL: http://www.edu.tw/clc/dict/

Cambridge International Dictionaries
Cambridge International Dictionaries online web site provides English words searching from different dictionaries. The dictionaries include Cambridge International Dictionary of English, Cambridge Dictionary of American English, Cambridge International Dictionary of Phrasal Verbs and Cambridge International Dictionary of Idioms.
URL: http://www.cup.cam.ac.uk/elt/dictionary/

Collins Cobuild Student's Dictionary


Collins Cobuild Student's Dictionary is in co-operation of Sprachwissenschaftliches Institut, COLLINS Birmingham University International Language Database and Ministerium fur Wissenschaft und Forschung des Landes NRW.

URL: http://www.linguistics.ruhr-uni-bochum.de:8099/

WordNet
WordNet, an electronic lexical database, is considered to be an important resource available to researchers in computational linguistics, text analysis, and many related areas. Its design is inspired by current psycholinguistic and computational theories of human lexical memory. English nouns, verbs, adjectives, and adverbs are organized into synonym sets, each representing one underlying lexicalized concept. Different relations link the synonym sets.
URL: http://www.cogsci.princeton.edu/~wn/

中文字譜 Chinese Character Genealogy :
An Etymological Chinese-English Dictionary
Chinese Character Genealogy(中文字譜) : An Etymological Chinese-English Dictionary : A state-of-the-art lexical product of Rick Harbaugh, then of the University of Pittsburg and now of Yale University
URL: http://zhongwen.com/

On-line Chinese tools
On-line Chinese tools(線上中文工具) is maintained by Erik E. Peterson. This web site provides tools to assist people in learning and using Chinese language. Content of the web site includes "Character Flashcards", "Chinese/English dictionary", "Chinese Namer", and "Western/Chinese Calendar Converter".
URL: http://www.mandarintools.com/