Learn the meaning of myriad, a literary word for an extremely large number of something, and how to use it in sentences. Find synonyms, pronunciation, pictures and more in the Oxford Advanced Dictionary app. Myriad definition: a very great or indefinitely great number of persons or things.. See examples of MYRIAD used in a sentence. MYRIAD definition: 1. a very large number of something: 2. very large in number, or having great variety: 3. a very…. Learn more. Master the word "MYRIAD" in English: definitions, translations, synonyms, pronunciations, examples, and grammar insights - all in one complete resource.