This character is a Math Symbol and is commonly used, that is, in no specific script.
The glyph is not a composition. Its width in East Asian texts is determined by its context. It can be displayed wide or narrow. In bidirectional text it acts as Other Neutral. When changing direction it is mirrored. If its East Asian Width is “narrow”, U+22BF forms a word with similar characters, which prevents a line break inside it. Otherwise it allows line breaks around it, except in some numeric contexts.
The CLDR project calls this character “right triangle” for use in screen reading software. It assigns these additional labels, e.g. for search in emoji pickers: mathematics, right, right-angled, triangle.
The Wikipedia has the following information about this codepoint:
⊿ may refer to:
Right triangle, a triangle containing a right angle
Triangle (Perfume album), the third album of techno-pop group Perfume
Representations
System
Representation (click value to copy)
Nº
8895
UTF-8
E2 8A BF
UTF-16
22 BF
UTF-32
00 00 22 BF
URL-Quoted
%E2%8A%BF
HTML hex reference
⊿
Wrong windows-1252 Mojibake
⊿
HTML named entity
⊿
Encoding: BIG5 (hex bytes)
A1 E9
Encoding: BIG5HKSCS (hex bytes)
A1 E9
Encoding: CP932 (hex bytes)
87 99
Encoding: CP950 (hex bytes)
A1 E9
Encoding: EUC_JIS_2004 (hex bytes)
AD F9
Encoding: EUC_JISX0213 (hex bytes)
AD F9
Encoding: GBK (hex bytes)
A8 53
Encoding: GB18030 (hex bytes)
A8 53
Encoding: ISO2022_JP_2004 (hex bytes)
1B 24 28 51 2D 79 1B 28 42
Encoding: ISO2022_JP_3 (hex bytes)
1B 24 28 4F 2D 79 1B 28 42
Encoding: SHIFT_JIS_2004 (hex bytes)
87 99
Encoding: SHIFT_JISX0213 (hex bytes)
87 99
Adobe Glyph List
righttriangle
RFC 5137
\u'22BF'
Bash and Zsh inside echo -e
\u22BF
C and C++
\u22BF
C#
\u22BF
CSS
\0022BF
Excel
=UNICHAR(8895)
Go
\u22BF
JavaScript
\u22BF
Modern JavaScript since ES6
\u{22bf}
JSON
\u22BF
Java
\u22BF
Lua
\u{22BF}
Matlab
char(8895)
Perl
"\x{22BF}"
PHP
\u{22bf}
PostgreSQL
U&'\22BF'
PowerShell
`u{22BF}
Python
\u22BF
Ruby
\u{22bf}
Rust
\u{22bf}
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