An English dictionary is the most important thing you will need when learning English. A good dictionary will help you learn hundreds of new words, improve your pronunciation and grammar. You can read more about why it is important to get a good English dictionary in another article.

English-English dictionaries

When you think of a dictionary, you usually think of a bilingual dictionary. For example, an English-German dictionary or a French-English dictionary. There is also another kind of dictionary: an English-English (monolingual) dictionary.

Such a dictionary is written only in English. English words are not translated, but they are defined or explained in English. For example, if you look up the word criticize in an English-English dictionary, you will read something like this:

to criticize = to say negative things about; to talk about the mistakes of

Why English-English dictionaries are better than bilingual dictionaries:

  • English definitions are real English phrases with grammar and words. If you read them regularly, you will automatically memorize the grammar and words.
  • English definitions let you learn more. You will often look up a word because it was part of the definition for another word. For example, if you look up the word naughty, you will read:
    If you say that a child is naughty, you think that he or she is behaving badly or is disobedient. [Collins COBUILD English Dictionary]

    If you don't know the words disobedient and behave, you will have to look them up. So instead of one word, you will have learned three words!

Don't be afraid of using an English-English dictionary. If you can understand this article, you can definitely understand the definitions in an English-English dictionary.

Dictionaries for learners and for native speakers

There are two kinds of English-English dictionaries: dictionaries for learners and dictionaries for native speakers. Dictionaries for native speakers are used by Americans, Britons, etc. to look up very difficult words, such as tintinnabulation. Dictionaries for learners are used by people who are learning English as a second language.

Dictionaries for native speakers usually have more words than dictionaries for learners, but the definitions are complicated, and there are fewer example sentences. Therefore your first dictionary should be a dictionary for learners. Later, you will need other dictionaries — for example, a dictionary of phrasal verbs and a big dictionary for native speakers.

Software dictionaries

If possible, get a software dictionary instead of a paper one. Here are some reasons why:

  • Quick searching. Software dictionaries let you look up words very quickly. Typing a word on your keyboard is much, much faster than turning pages in a large, heavy book.
  • Easy copying. If you're making your own SuperMemo collection for learning English, you can select whole sentences and definitions in the dictionary, and copy them to your new items.
  • Recordings. In many software dictionaries, you can listen to recordings which show you how to pronounce a word. Recordings cannot replace phonetic transcriptions (see below), but they are certainly a useful feature.
  • More information/clearer layout. Paper dictionaries have limited space, which is why they are printed in a small font and the layout is very crowded. A computer dictionary has more space, so it can give more information (e.g. more example sentences) or it can present the same information in a clearer way (bigger font, blank lines, etc.).

Why is quick searching so important? Because if you want to learn English well, you should look up lots of words, and a paper dictionary discourages you from that. You want to look up a word, you look at the huge book with 1500 pages, think "Ah, never mind", and you never learn that word. With a software dictionary, once you see how easy it is, you will start looking up hundreds of words every week. And your English will get a huge boost.

Note: The advice in this article applies to both book dictionaries and to software dictionaries. However, the quality of a software dictionary also depends on other features (e.g. ease-of-use, software speed), which are not discussed here.

Phonetic transcription for every word

A good dictionary must give phonetic transcription for every word. Phonetic transcription tells you how to pronounce a word. Without it, you can't say the word properly — you can only read it or write it.

The transcription should be based on the International Phonetic Alphabet (IPA), which is the main phonetic alphabet used all over the world. Here is what IPA-based phonetic transcription looks like:

dictionary definition of the word 'image'
[Longman Active Study Dictionary of English]

Here, the phonetic transcription is marked in yellow. It tells you that image is pronounced like this. (sound recording in .wav format)

Many dictionaries (especially ones published in the US) use their own phonetic symbols (and not IPA symbols). These are a little hard to use, and we do not recommend them to beginners. Some dictionaries give phonetic transcription only for "the most difficult words" (usually less than 5% of all words). Such dictionaries are almost useless to learners, because all English words are difficult if you are not a native speaker. We do not recommend them.

If you want to check if a dictionary uses IPA-based transcription, look at the pronunciation symbols used in the dictionary and compare them with the IPA symbols in our table of phonetic symbols.

Example sentences for every word

A good dictionary must give example sentences for every word. Example sentences are English sentences which contain the word. Some dictionaries give them after the definition of a word. Example sentences are marked in yellow in this picture:

dictionary definition of the word 'dizzy'
[Longman Dictionary of English Language and Culture]

Example sentences are not just helpful — they are actually more important than definitions. While a definition tells you the meaning of a word and (sometimes) gives you some grammatical information, example sentences have at least three advantages:

  1. They let you check if you've understood the definition correctly. The meaning of a word can become much clearer if you read a few sentences with the word.
  2. They show you how to use a word in sentences. Many words "go with" certain grammar structures (e.g. important is often used in the phrase "It is important to...") or words (e.g. weather goes with forecast and not e.g. prediction). Example sentences present this information in a clear way. You can easily imitate them to make your own natural sentences.
  3. They program your brain to produce correct English sentences. If you read an English sentence, there is a good chance that it will stay in your head, and that you will be able to build a similar sentence (or part of a sentence) to express your thoughts another day. So the more English sentences you read, the more you can produce.

(Read more about why example sentences are so important)

Other things to look for

  • Simple definitions. The definitions should be easy to understand. If something can be simple, it should be simple. See example of a simple dictionary definition.
  • Useful definitions. If possible, the definitions should tell you how to use the word. Generally, longer definitions are better, because they give more information. See example of a useful dictionary definition.
  • Both British and American English. Your dictionary should have both British and American words. Also, both British and American pronunciation should be given, because both are used in today's world.
  • Phrasal verbs and idioms. There are special dictionaries for these, but every English dictionary should have the most common phrasal verbs and idioms.
  • Pictures. Sometimes you can understand a picture better than a definition. See this example.

How many and how big?

It is a good idea to have at least two dictionaries: a large one (about this size) to use at home, and a small (pocket) one to carry with you. For example, you can bring your small dictionary to English classes.

It is an even better idea to have at least two large dictionaries. What for? Well, it's about example sentences. Two example sentences are better than one; four are better than two. With more examples, you have a more complete picture of how a word is used and you can express more in English yourself.

Recommended English dictionaries for learners

For your first learner's dictionary, we recommend the Collins COBUILD Advanced Learner's English Dictionary (our review of this dictionary). It's a large dictionary with IPA-based phonetic transcriptions and great example sentences for every word. But the best thing are the definitions: they are very friendly, and they really tell you how to use a word. The CD-ROM (included with the book) allows easy and fast searching, and also includes a Wordbank with lots of additional example sentences.

You can buy the Collins COBUILD Advanced Learner's English Dictionary at Elearnaid in hardcover ($37) and paperback ($28). Both include the software version of the dictionary on CD-ROM.

For a small dictionary that you can take everywhere you go, we recommend the Oxford Learner's Pocket Dictionary. It is very small (it will fit in your palm), but has a lot of information. You can get the dictionary from Amazon.co.uk.