There are plenty of online dictionaries, but only a few cater to kids. Look for an online dictionary for kids to have age-appropriate definitions and language. Here are three little gems to help your children with their homework.
The Yahoo! Kids dictionary is an online edition of the American Heritage Dictionary by Houghton Mifflin. A search with Yahoo! Kids provides a list of possible words meeting the query. For example, the word "earthquake" returns results for both "earthquake" and "earthquake engineer." The dictionary provides suggestions for misspelled words. Click on the word of interest and you'll receive an in-depth result, including a sound file with the word pronunciation, multiple definitions (when appropriate), and the etymology (word origin). This is a great dictionary for kids.
Word Central uses the Merriam-Webster dictionary to provide results. If a user misspells a word, the dictionary will provide suggestions for the correct spelling. It also provides suggestions for words that may have multiple interpretations. For example, a search for "Scientist" offers a number of options including "earth scientist," "social scientist" and "political science." Each definition includes a sound file for pronunciation. Nice dictionary for kids.
This dictionary is geared towards very young learners and is designed to be browsed, rather than searched. It behaves more like an encyclopedia than a dictionary. Each entry has an illustration and a couple of sentences about the topic. Many entries include a link to find more information. The words in the Little Explorers dictionary range from extremely common ("hair") to relatively obscure ("Queen Alexandra's birdwing butterfly" - the largest butterfly in the world, according to Little Explorers).
Wordsmyth is a full-featured dictionary including pronunciation, animation, synonyms, photographs and etymology. The Children's dictionary search box is on the lower left hand side of the screen. Unfortunately, they are transitioning their site to a membership system. Most features over and above the basic definition will require registration and/or a premium (paid) membership.