Voycabulary
Online dictionary and thesaurus web linking lookup reference tool.
voycabulary.com

bab.la Online Dictionaries
A language portal that offers dictionary translations in several languages, including 24 English bilingual dictionaries. In addition to language quizzes and games, vocabulary lessons, as well as synonyms, pronunciation, sample and context sentences.
en.bab.la

Hyperdictionary.com
Displays definitions with each individual word in the definition hyperlinked to its definition.
hyperdictionary.com

Historical Thesaurus of English
Contains the vocabulary of English from the earliest written records to the present, with known recorded dates of usage, taken from the Oxford English Dictionary.
libra.englang.arts.gla.ac.uk

The Wordsmyth S.A.T. Dictionary
Based on a frequency analysis, includes the 2000 words appearing most frequently on S.A.T. tests.
lightlink.com

The Wordsworth Compendium
Program containing over 516,000 English words and phrases to solve word puzzles. Useful for the search and manipulation of words in all aspects of logological activities.
dictionary-thesaurus.com

Hutchinson Dictionary of English Useage
Hutchinson Dictionary of English Usage can explain the difference and guide your choice, so search the 1600 entries to find the precise word to convey your meaning.
tiscali.co.uk

The Newbury House Online Dictionary
Search over 40,000 entries to get clear concise definitions and when available related pictures.
nhd.heinle.com

DataSegment.com: Online Dictionary
Find definitions by alphabetical browsing or word lookup. Powered by several print dictionaries.
onlinedictionary.datasegment.com

Merriam-Webster's OnLine Dictionary
Official site for the reference publisher. Includes online versions of the collegiate dictionary and thesaurus.
merriam-webster.com

Die.net Online Dictionary
Cross-referenced definitions, spelling correction, and searches from WordNet, Webster's, and a variety of specialized sources. Supports regular expressions and the DICT protocol.
dictionary.die.net

Mike's English/American Dictionary
Fun look at the differences between US English and UK English. Written by the Brit who lived in Tossa Lane Texas.
effingpot.com

UltraLingua Online Dictionary
Searchable dictionary of the English language, with standard, reverse and phonetic lookup. Also links to a range of other language resources.
ultralingua.net

WordNet - a Lexical Database for English
English nouns, verbs, adjectives and adverbs are organized into synonym sets, each representing one underlying lexical concept.
wordnet.princeton.edu

Oxford Dictionaries
Online language dictionaries in English, French, Spanish, German and Italian languages. Also, provides a variety of language tools including grammar, synonyms, games and quizzes, word lists and more.
oxforddictionaries.com