Throw away your dusty old dead tree dictionaries! They are either too bulky (and expensive) to use conveniently, and not updated regularly enough, or they are too small to cover all the words you might need. It's the 21st century, so lets embrace all the free online dictionaries available to us!
When discussing the top free resources for language learning, I wanted to give tools that weren't language specific, and as such I included the following multilingual dictionaries first:
Some of these can actually be good dictionaries for specific languages, and as good as, or better than many dedicated specific language dictionaries. (In the comments, I got suggestions for other great multilingual dictionaries: The Free Dictionary, which is a monolingual dictionary in multiple languages! Just click the flags on the left, and Linguee for a bilingual dictionary that gives you the words in context rather than just translations or definitions, and is good for several languages).
I am a big fan of Wordreference for major European languages, especially French, Spanish, and Italian, since I generally find what I'm looking for there, either within their dictionary, or from the forum questions that come up in dictionary searches. It is also good for looking up conjugations of verbs in these languages if you are not sure. Google Translate seems to be the easiest one to use for less common languages, although I welcome alternatives below!
As well as these, I highly recommend using Wikipedia to search for the word in English and see a possible translation in the left. This is obviously better for proper names, or specific items (not verbs etc.). Otherwise, look it up in the Wikipedia specific to that language and see its English or other translation on that page. Finally, I like to use Google Image search to give myself a visual understanding of the word, without relying on translations.
Having said that, in this post, I want to list as many free dictionary websites that cater better to specific languages. As with the free-resources post, I will strive to keep this post as updated as possible, so I will list just a few at first and then hope that your comments can help me expand this list to make it a nice go to dictionary.
Also keep in mind that you can use many of these online dictionaries in conjunction with Learning With Texts for quick access to translations while you read.
Bilingual (and monolingual) dictionaries:
Now, keep in mind that I would highly recommend you don't rely too much on bilingual dictionaries!! They can make us lazily just accept translations rather than truly try to understand a phrase and its component words, through context. If you want to start thinking in that language, then you should aim to learn the language via that language asap, and monolingual dictionaries are a great way to do that.
Their purpose of a dictionary for anyone but tourists should always be to help you learn a language, rather than to replace the learning process with instant translations. It's why I opt to use monolingual dictionaries as soon as possible and have tried to include as many here below as possible.
Feel free to share both bidirectional dictionaries and monolingual dictionaries in the comments, especially for languages that I haven't listed, and (as long as they are truly useful/extensive and free) I'll add them here! Also let me know your feedback on the ones I have included, in case you find any of them less than adequate compared to alternatives.
As an addition, if you don't find a monolingual dictionary for the language you want among those below, check out the many languages of Wiktionary and use the one in your target language!
This list is alphabetic – if you can't find the language you are learning here yet, check out the multilingual dictionaries linked above.
American Sign Language:
- ASL pro have a very useful dictionary for learners of this language, where you click through the alphabet and see the word visually signed for you via real videos by signers for each and every word. Excellent online resource that is totally free! On the same page, at tabs at the top, you have further specific dictionaries for religious terms, conversational phrases and signs for babies.
- Signing Savvy is another one, although there are many features of this site blocked by paid membership. You can't search, but you can go through the alphabetic list to click particular ones without registering. A free registration only gives you 5 searches per day. In most cases to look up single words, you can find them in the alphabetic list without signing up.
- MoedictFor a more Taiwanese perspective
- And for Chinese-Chinese dictionaries, as well as several of the above, try Baidu
- http://prirucka.ujc.cas.cz/ Not good for definitions, but a useful one for conjugations and word inflections
- http://www.vandale.nl/ Bilingual and monolingual!
- http://www.lisaanmasry.com/online/search.php An absolutely essential resource for those of you learning the Egyptian dialect of Arabic!
- Oxford dictionaries have an online searchable monolingual English database that contains 145,000 words and definitions; very useful for English learners among you!
- Collins dictionary is a great monolingual one with several bilingual options too!
- Urban dictionary is a resource I use even myself to find new slang terms in English, and acroyms that I haven't come across yet, when they come up in casual situations
- Cambridge Learner's dictionary
- http://lernu.net/ Whenever I am not sure of a word in Esperanto, I use the free dictionary search tool built into this great Esperanto learning site. It works with many language combinations (Esperanto-English/French/Polish etc.)
- Reta Vortaro is a great one, popular with many Esperantists
- http://esperanto-panorama.net/vortaro/eoen.htm Not as extensive, but you can look through the entire list of terms alphabetically.
- You can also use a monolingual Esperanto dictionary on http://vortaro.net/, after a free registration.
- http://www.larousse.fr/dictionnaires Larousse's site is great for both their bilingual dictionaries, and for their French-French dictionary.
- http://littre.reverso.net/dictionnaire-francais/ Probably one of the more popular online monolingual dictionaries used by the French themselves
- Le grand dictionnaire terminologique, Quebec’s officially promoted dictionary – very useful for technical terms.
- http://www.crisco.unicaen.fr/des/ French monolingual dictionary of synonyms!
- http://dictionnaire.sensagent.com/a/fr-fr/ Another monolingual dictionary!
- dwds.de A monolingual German dictionary that goes into great detail for each word, including incredible context tabs and etymology.
- http://www.duden.de/ As above, also gives tonnes of info for each word
- http://dict.leo.org/ You can search directly between German and English/Spanish/French/Italian/Polish/Russian/Portuguese/Chinese, and many translations are offered.
- http://www.dict.cc/ Another fantastic choice for a bilingual German dictionary.
- http://de.pons.eu/ Yet another great alternative, that also has a tonne of combinations other than German-English. Note that you can use this as a great dictionary for Norwegian and other languages, as long as you use it through German.
- http://dict.tu-chemnitz.de/ And one more for luck!
- http://szotar.sztaki.hu/angol-magyar Bilingual dictionary. Also includes Hungarian to other languages.
- http://topszotar.hu/angolmagyar/ Another bilingual option
- http://irishdictionary.ie/ Great single word dictionary, with accent mark clicks included if your keyboard isn't configured yet. It also presents verb conjugations.
- http://focal.ie/ This dictionary is better for technical terminology
- http://www.potafocal.com A great alternative if you don't find what you are looking for in the above two links.
- http://www.treccani.it/vocabolario/italiano/ Extensive monolingual Italian dictionary
- http://www.excite.co.jp/dictionary/ Monolingual and bilingual!
- http://dictionary.goo.ne.jp/ This lets you look up a monolingual dictionary, a bilingual one and a Japanese-Chinese dictionary all at the same time!
- http://www.alc.co.jp/ This one includes a lot of example sentences
- http://www.csse.monash.edu.au/~jwb/cgi-bin/wwwjdic.cgi?1C (For Japanese to English)
- http://www.dicionarioinformal.com.br/ Great monolingual dictionary!
- http://www.priberam.pt/dlpo/ – Monolingual dictionary with both a European and a Brazilian search option for Portuguese
Sign Language (Various sorts)
- http://www.spreadthesign.com/ Doesn't cover many words, but it does separate the signs based on which country, if you are learning several different national signs, or a non-American one!
- http://lema.rae.es/drae A good monolingual Spanish dictionary from the Real Academia Española themselves!
- http://www.tubabel.com/ A monolingual Spanish dictionary of slang, sort of like a Spanish version of Urban Dictionary mentioned above!
- http://www.spanishdict.com/ A good bilingual Spanish dictionary