Wiktionary is an online dictionary created by the Wikimedia Foundation. It is a free, collaborative, multilingual dictionary project that includes over 3 million entries in over 250 languages. It provides definitions, pronunciations, etymologies, translations, and other information related to words. Wiktionary also includes the ability to search by language, part of speech, and other criteria. With its extensive language coverage, Wiktionary is a great resource for people looking for translations, synonyms, and antonyms. It is also a helpful source for students of language and linguistics, providing detailed information about syntax, grammar, and usage.