Being able to check the definition and spelling of words is essential for communicating clearly and for not making a fool of yourself by using words incorrectly. Dictionaries make this possible. And online dictionaries make it quick and easy.
Here is an alphabetized list of the most popular online dictionaries and my opinion of the clarity of their user interfaces. Some sites present too much distracting information, such as featured videos, words of the day, hot topics, and other material unrelated to the word you are trying to understand. For a similar reason, I prefer sites without ads, since advertisements divert attention and waste time. Of course this might not affect you, if you use an ad blocker.
The only two sites that qualify as being clear, ad-free, and fast are Wiktionary and Wordnik.
Wiktionary has the clearest interface. The grouping of definitions by parts of speech, the numbered and bulleted lists, and the use of font types and color make it easy to quickly grasp the information. Furthermore, Wiktionary shows words not only as they are used in English, but also how they are used in many other languages.
Share your thoughts in the comment section below.
What is your preferred online dictionary? Why?