U+03BF "ο" Greek Small Letter Omicron Unicode Character

U+03BF "ο" Greek Small Letter Omicron is the fifteenth letter of the Greek alphabet, representing the short vowel sound /o/ in Ancient Greek and the close-mid back rounded vowel /o̞/ in Modern Greek. It is distinct from the Latin letter "o" in both shape and typographic context, though it appears visually identical in many fonts. In mathematics and science, omicron is used less frequently than other Greek letters, but it has been adopted as the symbol for the fifteenth iteration or subtype in various naming conventions, such as in the classification of COVID-19 variants.