Omicron Symbol Ο ο — Copy, Paste and Type It
The omicron symbol is the 15th letter of the Greek alphabet, written ο in lowercase and Ο in uppercase. It is pronounced /ˈoʊmɪkrɒn/ (“OH-mih-kron”). Click a symbol to copy it.
Copy the omicron symbol
Omicron is invisible: Ο vs O vs 0
Omicron is the one Greek letter that is identical to a Latin letter in both cases: Ο (U+039F) looks like O (U+004F), and ο (U+03BF) looks like o (U+006F). That is why LaTeX has no \omicron command at all — you type o and O.
The invisibility cuts both ways. A Greek omicron hidden inside an English word (a “homoglyph”) makes the word fail spell-check, search and password checks, and is a known trick in phishing domain names. If you paste ο into ordinary English text, it will look right and behave wrong. Use the Greek code points only for actual Greek text.
Not sure which Greek letter you need? See all 24 Greek symbols with codes.
Omicron codes — Unicode, HTML, LaTeX and Alt codes
| Char | Unicode | HTML entity | HTML decimal | HTML hex | CSS | JavaScript | LaTeX | Windows | Mac |
|---|---|---|---|---|---|---|---|---|---|
| ο | U+03BF | ο | ο | ο | \03BF | \u03BF | o | 03BF then Alt + X (Word) | Greek keyboard O |
| Ο | U+039F | Ο | Ο | Ο | \039F | \u039F | O (no \Omicron command) | 039F then Alt + X (Word) | Greek keyboard Shift + O |
Need the characters without any explanation? Open the Greek letters copy-paste sheet.
How to type the omicron symbol
Windows
- Fastest: press
Win + .to open the emoji panel, choose the Symbols tab (Ω), then Greek. - There is no classic Alt code for omicron — the old DOS code page only included a handful of Greek letters (α Γ π Σ σ τ Φ Θ Ω δ φ ε). Use one of the other methods.
- Microsoft Word: type
03BFand pressAlt + Xfor ο;039FthenAlt + Xfor Ο. Word converts it in place.
Mac
- Add the Greek keyboard in System Settings → Keyboard → Input Sources, then
Otypes ο andShift + Otypes Ο. - Or open the Character Viewer with
Ctrl + Cmd + Spaceand search “omicron”.
iPhone and Android
- iOS: Settings → General → Keyboard → Keyboards → Add New Keyboard → Greek. Tap the globe key to switch.
- Android (Gboard): Settings → Languages → Add keyboard → Greek.
- Or copy the character from the top of this page.
LaTeX
o— lowercase ο in math mode (there is no \omicron)Oor\mathrm{O}— capital Ο (there is no\Omicron)
HTML, CSS and code
- HTML:
οorοorο - CSS:
content: "\03BF"; - JavaScript / JSON:
"\u03BF"— Python:"\u03bf" - In source code, prefer the escape over the pasted glyph — it survives every file encoding.
Full typing guide for every platform, including Linux and Google Docs → how to type Greek letters.
What does omicron mean?
Health
- Omicron — the SARS-CoV-2 variant named by the WHO in November 2021
Mathematics
- big-O notation is sometimes called big-Omicron
Astronomy
- ο Ceti (Mira) — a famous variable star
Omicron at a glance
- Position
- 15th of 24
- Uppercase / lowercase
- Ο ο
- Greek name
- όμικρον
- Pronunciation
- /ˈoʊmɪkrɒn/
- Numeric value
- 70
- Became
- Latin O and Cyrillic О
Frequently asked questions
What is the omicron symbol?
Omicron (Ο ο) is the 15th letter of the Greek alphabet, pronounced /ˈoʊmɪkrɒn/ (“OH-mih-kron”). It is most often used for the COVID-19 variant; identical to Latin o.
How do I type the omicron symbol on a keyboard?
On Windows, press Win + . → Symbols → Greek, or in Microsoft Word type 03BF and press Alt + X. On a Mac, switch to the Greek keyboard and press O (Shift + O for the capital). Or simply copy it from the top of this page.
What is the LaTeX command for omicron?
Use o for lowercase ο (there is no \omicron command), inside math mode. There is no \Omicron command for the capital: it looks identical to the Latin O, so you type O.
What is the Unicode and HTML code for omicron?
Lowercase ο is U+03BF, written in HTML as ο or ο. Capital Ο is U+039F, written Ο or Ο.