Greek Capital Letter Xi Ξ

The Greek Capital Letter Xi character (Ξ) is a standard HTML entity defined in the HTML specification. In HTML source code, it can be written using the named entity reference Ξ, the decimal numeric character reference Ξ, or the hexadecimal numeric reference Ξ. The character is assigned Unicode code point U+039E in the Universal Character Set.

Greek capital xi (Ξ) has a distinctive three-horizontal-lines appearance unlike any Latin letter. It is used in particle physics for the Xi baryon and occasionally in mathematical notation. Its unique visual form makes it immediately recognizable as a Greek letter.

Greek letter entities are indispensable for scientific papers, engineering documentation, statistical analyses, and mathematical content published on the web. From physics equations using alpha and omega to statistical formulas featuring sigma and mu, these entities allow content authors to include Greek characters reliably without requiring specialized fonts or complex Unicode input methods on the keyboard.

When deciding how to encode the Greek Capital Letter Xi character in your HTML documents, the named entity Ξ is generally the most readable choice for developers reviewing or maintaining source code. The decimal form Ξ and hexadecimal form Ξ are equally valid alternatives that work in contexts where named entities may not be supported, or when generating HTML output programmatically from server-side code. All three representations produce identical visual output in every modern web browser.

Use the capital xi entity in particle physics (Xi baryon Ξ), mathematical notation where a distinctive capital letter is needed, and Greek-language text. Its unique appearance makes it useful when you need a symbol that cannot be confused with Latin letters.