Combining Overline
HTML Entity Browser Test:

U+0305 is the Unicode hex value of the character Combining Overline, which is categorized as "non-spacing mark" in the Unicode 6.0 character table.

"Combining Overline" was previously named "NON-SPACING OVERSCORE" in older versions of Unicode.

Unicode Character Information
Unicode Hex U+0305
General Category Non-Spacing Mark [Code: Mn]
Canonical Combining Class 230
Bidirectional Category NSM
Mirrored N
Unicode Character Encodings
Combining Overline HTML Entity ̅ (decimal entity), ̅ (hex entity)
Windows Key Code Alt 0773 or Alt +03051
Programming Source Code Encodings Python hex: u"\u0305", Hex for C++ and Java: "\u0305"
UTF-8 Hexadecimal Encoding 0xCC85
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 0773) will only work on computers with support for this Unicode character in the active code page. The hexadecimal alt code (Alt +0305) will work for all Unicode characters provided Hex input from the numeric keypad is enabled.
* If the Combining Overline character does not display correctly in your browser, you may not have a Unicode font on your system that supports this particular symbol.