O

O, 15th letter and 4th vowel in the English alphabet and other alphabets of Western Europe. It was originally a Phoenician character that stood for a guttural breathing sound. The Greeks adopted this sign to represent omicron, or the short o, and added a separate sign for the long o, omega. A single letter, standing for both sounds, was incorporated into the Latin alphabet. In English the letter o represents a long sound, as in the words old and bone; and a short sound, as in hot and golf. The letter also stands for the sounds heard in shorn, wolf, son, and do. The long o sound is indicated by a variety of spellings, as in the words sew, dough, and foe.