Omicron

Omicron (uppercase Ο, lowercase ο, literally "small o": Όμικρον, o mikron, micron meaning 'small' in contrast to omega) is the 15th letter of the Greek alphabet. In the system of Greek numerals it has a value of 70. It is rarely used in mathematics because it is indistinguishable from the Latin letters O, o and easily confused with the digit 0. This letter is derived from the Phoenician letter Ayin. In modern Greek, omicron represents the sound [ɔ]. Letters that arose from omicron include Roman O and Cyrillic O.

In Unicode the capital letter is codepoint U+039F and the lowercase is U+03BF.

The upper-case letter of omicron (O) was originally used in mathematics as a symbol for Big O notation, representing the asymptotic rate of growth of a function.

In popular culture

• Omicron is frequently used to designate the thirteenth star in a constellation group, using a combination of magnitude and position.^[1] Stars with the omicron designation include Omicron Andromedae, Omicron Ceti, and Omicron Persei. The last of these is well-known due to its use as a setting in science fiction, including Star Trek, Mystery Science Theater 3000, Transformers, and Futurama.

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