For General Definitions:
* Dictionary.com: A comprehensive online dictionary with definitions, synonyms, antonyms, and more. They also offer a Thesaurus and a Pronunciation Guide.
* Merriam-Webster: Another well-established online dictionary with a clean interface and detailed definitions, including etymology and usage examples.
* Oxford English Dictionary (OED): The gold standard for historical definitions and etymology. Requires a subscription for full access but offers a free trial.
* Google Search: Simply type the word you want to define into Google, and it will often provide a quick definition from their database.
For Specialized Definitions:
* Wikipedia: While not a dictionary, Wikipedia is an excellent resource for finding definitions of terms related to specific subjects, often with detailed explanations and context.
* Jargon.com: A great source for understanding slang, colloquialisms, and informal language.
* Online Encyclopedias: Depending on the subject, you might find dedicated online encyclopedias such as Britannica or Encyclopedia.com.
For Language Learners:
* WordReference: A multilingual dictionary with definitions, translations, forums, and learning tools.
* Cambridge Dictionary: Another good dictionary focused on English language learning, offering clear definitions and usage examples.
* Macmillan Dictionary: Offers definitions, examples, and collocations, making it great for understanding how words are used in context.
Other Useful Tools:
* Thesaurus.com: For finding synonyms and antonyms.
* Wordnik: Provides definitions, synonyms, antonyms, and a visual word map.
Important Tips:
* Check the source's authority: Make sure the website you're using is reputable.
* Consider the context: The definition of a word can vary depending on the context in which it's used.
* Use multiple resources: Don't rely on just one dictionary for definitions. Compare information from different sources to get a well-rounded understanding.