Omicron facts for kids
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Quick facts for kids Greek alphabet |
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|---|---|---|---|
| Αα | Alpha | Νν | Nu |
| Ββ | Beta | Ξξ | Xi |
| Γγ | Gamma | Οο | Omicron |
| Δδ | Delta | Ππ | Pi |
| Εε | Epsilon | Ρρ | Rho |
| Ζζ | Zeta | Σσ | Sigma |
| Ηη | Eta | Ττ | Tau |
| Θθ | Theta | Υυ | Upsilon |
| Ιι | Iota | Φφ | Phi |
| Κκ | Kappa | Χχ | Chi |
| Λλ | Lambda | Ψψ | Psi |
| Μμ | Mu | Ωω | Omega |
| Other letters | |||
| Ϝϝ | Digamma | Ϟϟ | Koppa |
| Ϛϛ | Stigma | Ϡϡ | Sampi |
| Ͱͱ | Heta | Ϸϸ | Sho |
| Ϻϻ | San | ||
Omicron (uppercase Ο, lowercase ο) is the 15th letter of the Greek alphabet. This letter comes from an ancient Phoenician letter called ayin:
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In ancient Greek, omicron made a short "o" sound. This was different from omega, which made a long "o" sound. The word "omicron" literally means "little O" (o mikron), while "omega" means "great O" (ō mega).
Today, in modern Greek, both omicron and omega make the same "o" sound. Letters that came from omicron include the Roman letter O and the Cyrillic letter O. In the system of Greek numerals, omicron stands for the number 70.
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How Omicron is Used
Besides being a letter in the alphabet, omicron is sometimes used in special ways in science and math. However, it's not used very often because its uppercase and lowercase forms (Ο ο) look exactly like the Latin letter "o" (O o) and are hard to tell apart from the number "zero" (0).
Omicron in Numbers
There were different ways to write numbers in Greek. The most common way, used a long time ago, used omicron (Ο or ο) to mean the number 70.
Also, the letter omicron is used to mark the fifteenth item in a list that uses Greek letters. For example, in Euclid's famous book Elements, when he drew geometric shapes, he would label different points with letters. Using omicron was like labeling a point with the number 15.
Omicron in Space
Omicron is used to name the fifteenth star in a group of stars called a constellation. The stars are named based on how bright they are and where they are located. Some stars named with omicron include Omicron Andromedae, Omicron Ceti, and Omicron Persei.
In ancient astronomy, a scientist named Ptolemy (who lived around 100-170 AD) used omicron in his tables of numbers. These tables used a special number system called sexagesimal (based on 60). In this system, omicron was used to show an empty space or a "zero" in the table. This helped avoid mistakes, much like how we use a dash (—) today to show that a space in a table is meant to be empty. It's a coincidence that the ancient omicron (ο) looks like our modern number zero (0).
Omicron in Medicine
The World Health Organization (WHO) uses letters from the Greek alphabet to name important types of SARS‑CoV‑2, which is the virus that causes COVID-19. On November 26, 2021, the name Omicron was given to the B.1.1.529 variant of concern of the virus.
Related pages
Images for kids
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This old stone carving from the 5th century BCE shows the word "ΠΡΟΤΟΣ ΑΧΣΟΝ" (meaning "first axon"). Notice how it uses O instead of Ω.
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See also
In Spanish: Ο para niños
