Greek Capital Lunate Sigma Symbol
HTML Entity Browser Test:

U+03F9 is the Unicode hex value of the character Greek Capital Lunate Sigma Symbol, which is categorized as "uppercase letter" in the Unicode 6.0 character table.

In addition, U+03F9 is a composite character comprising of one or more other Unicode characters modified or combined.

Unicode Character Information
Unicode Hex U+03F9
General Category Uppercase Letter [Code: Lu]
Canonical Combining Class 0
Bidirectional Category L
Decomposition Mapping <compat> 03A3
Mirrored N
Lowercase Version U+03F2
Unicode Character Encodings
Greek Capital Lunate Sigma Symbol HTML Entity &#1017; (decimal entity), &#x03F9; (hex entity)
Windows Key Code Alt 1017 or Alt +03F91
Programming Source Code Encodings Python hex: u"\u03F9", Hex for C++ and Java: "\u03F9"
UTF-8 Hexadecimal Encoding 0xCFB9
1 To type a Unicode symbol in Windows, hold down the ALT key and enter the decimal or hexadecimal code provided using the numeric keypad. The decimal alt code (Alt 1017) will only work on computers with support for this Unicode character in the active code page. The hexadecimal alt code (Alt +03F9) will work for all Unicode characters provided Hex input from the numeric keypad is enabled.
* If the Greek Capital Lunate Sigma Symbol character does not display correctly in your browser, you may not have a Unicode font on your system that supports this particular symbol.