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The letter "O" is the fifteenth letter and the fourth vowel in the Latin alphabet. It is used in the modern English alphabet and the alphabets of other Western European languages, as well as worldwide.

Identification Tips

In its uppercase form, "O" is a simple circle. The lowercase "o" is a smaller, but still circular shape. Both forms have remained consistent in design from Phoenician times to the present.

History

The letter "O" traces its origins back to the Phoenician letter 'ayin, which represented an eye and was drawn as such. Its sound value was that of a consonant, likely [ʕ]. The Greeks adapted it for the vowel sound /o/, and it was passed down to the Old Italic alphabets, including early Latin. The Greek alphabet later introduced a variation, Omega, to distinguish the long "O" sound from the short "O" sound of Omicron.

Use in Writing Systems

In English, "O" can represent a variety of sounds, including the "long" /oʊ/ as in "boat," which is often a diphthong, and the "short" /ɒ/ as in "fox." It can also represent /uː/ or /ʊ/ in digraphs like "oo," or the diphthong /ɔɪ/ in "oi" or "oy." In other contexts, it may represent /ʌ/, as in "son," or the semivowel /w/ as in "choir."

Other Languages

"O" is associated with open-mid back rounded vowel [ɔ], mid back rounded vowel [o̞], or close-mid back rounded vowel [o] in many languages. It can also represent various back vowels that are at least partly open.

Other Systems

In the International Phonetic Alphabet, "O" represents the close-mid back rounded vowel.

Related Characters

Descendants and related characters in the Latin alphabet include various forms of "O" with diacritics, such as "Ö" and "Ø," which are used to represent sounds not present in the original Latin and Greek alphabets.

Other Representations

In computing, "O" has specific Unicode and ASCII codes. It is also represented in Morse code, signal flags, semaphore, manual alphabets, and Braille.

See Also

The letter "O" is sometimes confused with the number zero due to their similar appearance in some typefaces. It is important to distinguish between the two, especially in contexts where both letters and numbers are used.