O

O is the fifteenth letter of the Latin alphabet.

In Greek (Omikron), Etruscan and Latin O stood for the vowel /o/. Although Semitic 'Ajin was used in some alphabets to transcribe [o], the sound value was usually consonantic: [?/] (as the Arabic letter 'Ajn).

A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z

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O is also:

• used in complexity theory and mathematics to describe the size of functions, using a notation called "Big O notation".
• the symbol for oxygen in the periodic table of the elements.
• a movie based on William Shakespeare's Othello and set in a high school. The duke is the basketball coach nicknamed "Duke", and the Othello role is a basketball star nicknamed "O". The movie is a very realistic portrayal of how adolescent jealousy can get out of hand, leading to deadly consequences.
• the name of a major magazine publication founded and edited by entrepreneur Oprah Winfrey.
• the stock symbol for Realty Income Corporation[?].