Omicron
/ˈɒmɪkrɒn/noun
The fifteenth letter of the Greek alphabet, written Ο or ο, representing a short o sound in Ancient Greek.
Did you know?Omicron’s name was created to contrast it with omega, whose name means “large O,” preserving an ancient Greek distinction between short and long vowel sounds.
Etymological Timeline
Classical Greek
Ancient Greek
ὂ μικρόν (ὸ mikrón)
“the small o; a descriptive name distinguishing the letter from omega”
Hellenistic Greek
Greek
ὀμικρόν (omikrón)
“small o, referring to the short-vowel letter Ο/ο”
Byzantine Greek
Greek
ὀμικρον (ómikron)
“the established name of the Greek letter”
Medieval Latin
Latin
omicron
“the Greek letter name borrowed into Latin scholarly usage”
17th Century
English
omicron
“the fifteenth letter of the Greek alphabet”
Modern English
English
omicron
“the letter Ο or ο; also used as the name of the SARS-CoV-2 variant designation”