O, the fourth vowel of the modern alphabet, corresponding to the Semitic ayin, which represented a breathing and not a vowel. The Semitic form may have derived from an earlier sign representing an eye., Ó, ó (o - acute) is a letter in the Czech, Dobrujan Tatar, Emilian-Romagnol, Faroese, Hungarian, Icelandic, Kashubian, Polish, Slovak, Karakalpak, and Sorbian languages. The symbol also appears in the Afrikaans, Catalan, Dutch, Irish, Nynorsk, Bokmål, Occitan, Portuguese, Spanish, Italian and Galician languages as a variant of the letter "o"., O is used to mean zero, for example when you are telling someone a phone number, or mentioning a year such as 1908., Learn how to type O with accent mark on Windows and Mac. Acute, grave, circumflex, tilde, and umlaut accents change O's pronunciation., The fifteenth letter of the English alphabet, called o and written in the Latin script. Alternative form of ο, the fifteenth letter of the Classical and Modern Greek alphabets, called omicron and(astronomy) used as an abbreviation of omicron in star names. The system's Bayer designation is o Persei. The system's Bayer designation is o Persei., ô (lexicography) A dictionary transcription for the THOUGHT vowel; also an orthographic o with a diacritic that marks it as having that value, as in the word "nor". Synonyms: ȯ, ö.