MegaDico is a community-powered, living dictionary of French slang and everyday language. It explains words and expressions through concise definitions, examples of use, and synonyms, with meanings contributed and rated by the people who use them. Visitors can browse popular entries, explore topics and rankings, or look up the word of the day.

Anyone can submit a definition instantly, without creating an account, and community votes help highlight useful contributions. The collection spans contemporary slang, regional expressions, internet vocabulary, and familiar terms from areas such as music, gaming, sport, gardening, and finance. Entries may include quotations and subject tags to provide context and make related words easier to discover.

MegaDico says content is removed only when it is illegal, and provides a reporting process for users to flag concerns; reports are reviewed by a human. The site also states that it operates without cookies or tracking and hashes IP addresses rather than storing them in clear text