Greek Capital Letter Omicron HTML entity Ο

Ο is the HTML entity for Greek Capital Letter Omicron Ο (U+039F). Copy Ο, Ο and the CSS, JavaScript, Python and URL escapes.

Entity: Ο
Code point: U+039F
Unicode name: GREEK CAPITAL LETTER OMICRON
Block: Greek and Coptic
Category: Uppercase letter (Lu)
Since: Unicode 1.1
Defined in: HTML 4.01 and HTML5

Codes to copy

HTML named	`Ο`Works in HTML; in XML only & < > " ' are predefined.
HTML decimal	`Ο`Works in HTML and XML.
HTML hex	`Ο`Works in HTML and XML.
CSS	`content: "\39F";`In a stylesheet, for ::before and ::after.
JavaScript	`"\u039F"`Also valid in JSON.
Python	`"\u039f"`Python 3 string literal.
Python by name	`"\N{GREEK CAPITAL LETTER OMICRON}"`Readable alternative using the Unicode name.
URL	`%CE%9F`Percent-encoded UTF-8 bytes, for a path or query value.
UTF-8 bytes	`CE 9F`2 bytes.
UTF-16	`039F`1 code unit, which is what JavaScript length counts.

When to use it

Ο writes U+039F (Greek Capital Letter Omicron), a capital letter from the Unicode Greek and Coptic block, encoded since Unicode 1.1. In mathematics, single Greek letters are usually set in italic; MathML or a maths font handles that automatically.

The name dates from HTML 4, so it works in every browser and in old email clients.

More greek letters

All greek letters · Every HTML entity · Encode or decode text

Source: the WHATWG HTML Standard list of named character references and the Unicode Character Database (Unicode 18.0).