An ordered set of all the letters used in a language, including letters with diacritical signs where appropriate, but not including punctuation marks. 2. An ordered set of all the symbols used in a language, including punctuation marks, numeric digits, nonprinting control characters, and other symbols. Note: Examples of alphabets include the Roman alphabet, the Greek alphabet, the Morse Code, and the 128 characters of the American Standard Code for Information Interchange (ASCII. )