Omicron — ο Greek Letter Symbol
ο
Omicron — ο / Ο
15th letter of the Greek alphabet · pronounced /ˈɒmɪkrɒn/
MathematicsLinguisticsComputer Science
Copy symbol
ο
Lowercase omicron
Ο
Uppercase Omicron
Technical reference
| Unicode (lowercase) | U+03BF |
| Unicode (uppercase) | U+039F |
| HTML entity | ο |
| HTML decimal | ο |
| LaTeX | o |
| Python / Unicode escape | \u03bf |
| Alt code (Windows) | Alt + 959 |
Uses in science & engineering
Big-O notation (computer science)
Describes the upper bound of algorithm complexity. Note: the O in Big-O is conventionally written as a Latin O, but derives from Omicron.
\(f(n) = O(g(n))\)
Omicron in linguistics
Represents the short “o” vowel in ancient Greek. Rarely used as a mathematical symbol due to similarity with the numeral 0.
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Orbital notation
Occasionally used to label circular or near-circular orbits in astrodynamics.
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Related symbols
How to insert in applications
Windows
Best option: copy from this page.
Or press Win + . to open emoji & symbols panel.
Alt codes work only in Word/Notepad with NumLock on and English layout — not in browsers.
Or press Win + . to open emoji & symbols panel.
Alt codes work only in Word/Notepad with NumLock on and English layout — not in browsers.
macOS
Press ⌃⌘Space → Character Viewer → search “omicron”
Microsoft Word
Type 03bf then press Alt+X
Google Docs
Insert → Special characters → search by name
Excel
Insert → Symbol → Subset: Greek → select symbol
LaTeX
Use in math mode: $ … $
Python
Use Unicode escape or chr()
HTML / CSS
Use HTML entity or decimal code