The MacMillan Dictionary, the Merriam-Webster's Learner's Dictionary and the Web-based YourDictionary.com all provide example sentences with their definitions. Oxford Dictionaries also provides example sentences for users with Silver or Gold subscriptions to OxfordDictionaries.com. Example sentences are also known as illustrative examples, illustrative phrases, illustrative quotations and illustrative sentences.
Example sentences give the reader a better understanding of a word and different ways to use it. Illustrative examples are one of the best ways to learn a given word's grammatical context, usage, connotation and meaning in specific fields. YourDictionary.com offers a useful search tool that allows the user to submit a word and receive a list of sentences with the word in context.