O

O (named o /ˈoʊ/, plural oes) is the fifteenth letter and a vowel in the ISO basic Latin alphabet. The letter was derived from the Semitic `Ayin (eye), which represented a consonant, probably, the sound represented by the Arabic letter ع called `Ayn. This Semitic letter in its original form seems to have been inspired by a similar Egyptian hieroglyph for "eye". The Greeks are thought to have come up with the innovation of vowel characters, and lacking a pharyngeal consonant, employed this letter as the Greek O to represent the vowel /o/, a sound it maintained in Etruscan and Latin. In Greek, a variation of the form later came to distinguish this long sound (Omega, meaning "large O") from the short o (Omicron, meaning "small o").