The meaning of ALPHANUMERIC is consisting of both letters and numbers and often other symbols (such as punctuation marks and mathematical symbols); also : being a character in an alphanumeric system. Alphanumeric definition: Consisting of both letters and numbers. Learn what alphanumeric characters are and how they are used in passwords, programming, file names and data representation. Find out why alphanumeric characters are valuable and see examples of their applications. Alphanumeric characters refer to the combination of Latin alphabet letters (A to Z — uppercase and lowercase) and Arabic numerals (0 to 9) . This set is commonly used in English and other languages based on the Latin script, especially in computing.