Lex Scripta: English Language Dictionaries

English Language Dictionaries
Macquarie Dictionary Online
PAID SUBSCRIPTION REQUIRED.
The leading Australian English-language dictionary, searchable on-line.
The Oxford English Dictionary
PAID SUBSCRIPTION REQUIRED.
The world's greatest dictionary, in English or any other language.
The New Oxford Dictionary of English
Free access to a limited version of the world's greatest dictionary.
Cambridge International Dictionary of English
Also includes Cambridge Dictionary of American English, Cambridge International Dictionary of Phrasal Verbs and Cambridge International Dictionary of Idioms.
Wordsmyth English Dictionary-Thesaurus
Claimed to be "The ONLY integrated English Dictionary and Thesaurus in electronic form".
The American Heritage Dictionary of the English Language
On-line, searchable version of a leading US dictionary.
The American Heritage Dictionary of the English Language
Alternative facility to search the same work.
Merriam-Webster OnLine
On-line, searchable version of the Merriam-Webster dictionary.
Webster's Revised Unabridged Dictionary, 1913 Edition
Another on-line version of Webster's, this time comprising 109,562 entries.
Hypertext Webster Gateway
Another interface for searching Webster's Dictionary.
American English Dictionary
Another on-line, searchable dictionary.
Newbury House Dictionary Online
Yet another on-line, searchable dictionary.
Infoplease Encyclopedia and Dictionary
Searchable encyclopædia and dictionary.
Collins Cobuild Students' Dictionary
On-line, searchable dictionary includes grammar, pronunciation and pictures.
Open Resources Online Dictionary
One more on-line, searchable dictionary.
ALLWords.com
Apart from functioning as an ordinary dictionary, this service allows you to find words beginning with, ending with, or containing specified letters.
Vocabulary Helper
A "sort of" dictionary, which offers definitions of and synonyms for the word entered, and gives examples of the word used in context.

Miscellania
xrefer
A marvellous resource. Search respources including Oxford Paperback Encyclopedia, Penguin Encyclopedia of Places, The Macmillan Encyclopedia 2001, Bloomsbury Dictionary of Contemporary Slang, Bloomsbury Good Word Guide, Bloomsbury Thesaurus, Oxford Companion to English Language, Oxford English Reference Dictionary, Penguin Rhyming Dictionary, Pocket Oxford Dictionary of Current English, Bloomsbury Biographical Dictionary of Quotations, Bloomsbury Thematic Dictionary of Quotations, Oxford Dictionary of Quotations, Bloomsbury Guide to Art, Grove Concise Dictionary of Music, Market House Books Encyclopedia of the Renaissance, Oxford Dictionary of Art, Oxford Dictionary of Music, Penguin Dictionary of Music, Macmillan Dictionary of Women's Biography, Penguin Biographical Dictionary of Women, Who's Who in the Twentieth Century (OUP), A Dictionary of Business (OUP), A Dictionary of Law (OUP), Dictionary of Accounting (OUP), Penguin Business Dictionary, Penguin Dictionary of Economics, Penguin International Dictionary of Finance, A Dictionary of Food and Nutrition (OUP), Concise Medical Dictionary (OUP), Dictionary of Medicines (OUP), Market House Books Dictionary of British History, Bloomsbury Dictionary of English Literature, Oxford Companion to English Literature, Bloomsbury Guide to Human Thought, A Dictionary of Science (OUP), A Dictionary of Scientists (OUP), Dictionary of Biology (OUP), The Penguin Dictionary of Psychology, The Penguin Dictionary of Sociology
VoyCabulary
A remarkable resource. Enter the URL of any web page. VoyCabulary converts all the words on the webpage into links to dictionaries, thesauri, or other Web lookups. Supports English, Spanish, German, French, Japanese, Dutch, Swedish, Portuguese, Russian, Hungarian, and Welsh words, as well as medical and computer terms, and acronyms.
The Devil's Dictionary
Searchable version of Ambrose Bierce's satiric dictionary.
The King's English by H.W. Fowler
On-line version of the famous grammar text.
OneLook Dictionaries
Not a dictionary, but a search engine which simultaneously checks 345 general and specialist dictionaries.
Wordbot
An extraordinary facility, offering "a robot assistant for looking up translations, definitions, synonyms, antonyms, references, etc. of words appearing in a document".
Symbols.com
A dictionary of symbols and ideograms.
Crossword Solver
Select the length of the word, insert known letters, and the blanks are filled. (Nifty for cheating at Scrabble, as well as crossword puzzles.)
Palindromes
For those who are easily amused.
Tongue Twisters
For those who are even more easily amused.
Wayne Magnuson English Idioms
Slang and Sayings

Poetical Dictionaries
The Semantic Rhyming Dictionary
Invaluable aid for would-be poets and song-writers.
WriteExpress Online Rhyming Dictionary
Similar, but inferior.
Lexical FreeNet Connected Thesaurus
An extraordinary device. Enter two non-rhyming words, and it will attempt to find two rhyming words with similar meanings.
ALLWords.com
Apart from functioning as an ordinary dictionary, this service allows you to find words beginning with, ending with, or containing specified letters.
Dictionary of Similes
For the unimaginative - similes by category.
Vocabulary of Alliteration
Fun, if not especially useful.
Glossary of Poetic Terms
"A Unique Guide for the Study of Poetry".
Dictionary of Symbolism
Defines words according to their poetic symbolism.

Historical Dictionaries
The Middle English Compendium
Dictionary and resources relating to Middle English.
Medieval Glossary
Glossary of Mediæval words, with emphasis on those related to weaponry.
Hwæt! Old English in Context
Dictionary of Old (Anglo-Saxon) English.