This character is a Other Symbol and is commonly used, that is, in no specific script.
The glyph is a square composition of the glyphs Glyph for U+0041Latin Capital Letter A, Glyph for U+0055Latin Capital Letter U. Its East Asian Width is wide. In bidirectional text it is written from left to right. When changing direction it is not mirrored. U+3373 offers a line break opportunity at its position, except in some numeric contexts.
The Wikipedia has the following information about this codepoint:
The astronomical unit (symbol: au or AU) is a unit of length defined to be exactly equal to 149,597,870,700 m. Historically, the astronomical unit was conceived as the average Earth-Sun distance (the average of Earth's aphelion and perihelion), before its modern redefinition in 2012.
The astronomical unit is used primarily for measuring distances within the Solar System or around other stars. It is also a fundamental component in the definition of another unit of astronomical length, the parsec. One au is equivalent to 499 light-seconds to within 10 parts per million.
Representations
System
Representation (click value to copy)
Nº
13171
UTF-8
E3 8D B3
UTF-16
33 73
UTF-32
00 00 33 73
URL-Quoted
%E3%8D%B3
HTML hex reference
㍳
Wrong windows-1252 Mojibake
ã³
Encoding: GB18030 (hex bytes)
81 39 E1 39
RFC 5137
\u'3373'
Bash and Zsh inside echo -e
\u3373
C and C++
\u3373
C#
\u3373
CSS
\003373
Excel
=UNICHAR(13171)
Go
\u3373
JavaScript
\u3373
Modern JavaScript since ES6
\u{3373}
JSON
\u3373
Java
\u3373
Lua
\u{3373}
Matlab
char(13171)
Perl
"\x{3373}"
PHP
\u{3373}
PostgreSQL
U&'\3373'
PowerShell
`u{3373}
Python
\u3373
Ruby
\u{3373}
Rust
\u{3373}
Click the star button next to each label to set this representation as favorite or remove it from the favorites. Favorites will be shown initially. (Favorites are stored locally on your computer and never sent over the internet.)