This character is a Math Symbol and is commonly used, that is, in no specific script.
The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it acts as Other Neutral. When changing direction it is not mirrored. The word that U+25FC forms with similar adjacent characters prevents a line break inside it.
The CLDR project calls this character “black medium square” for use in screen reading software. It assigns these additional labels, e.g. for search in emoji pickers: black, geometric, medium, square.
This character is designated as an emoji. It will be rendered as monochrome character on conforming platforms. To enable colorful emoji display, you can combine it with Variation Selector-16: ◼️ See the Emojipedia for more details on this character’s emoji properties.
The Wikipedia has the following information about this codepoint:
Geometric Shapes is a Unicode block of 96 symbols at code point range U+25A0–25FF.
Representations
System
Representation (click value to copy)
Nº
9724
UTF-8
E2 97 BC
UTF-16
25 FC
UTF-32
00 00 25 FC
URL-Quoted
%E2%97%BC
HTML hex reference
◼
Wrong windows-1252 Mojibake
â—¼
HTML named entity
◼
Encoding: GB18030 (hex bytes)
81 37 A2 33
RFC 5137
\u'25FC'
Bash and Zsh inside echo -e
\u25FC
C and C++
\u25FC
C#
\u25FC
CSS
\0025FC
Excel
=UNICHAR(9724)
Go
\u25FC
JavaScript
\u25FC
Modern JavaScript since ES6
\u{25fc}
JSON
\u25FC
Java
\u25FC
Lua
\u{25FC}
Matlab
char(9724)
Perl
"\x{25FC}"
PHP
\u{25fc}
PostgreSQL
U&'\25FC'
PowerShell
`u{25FC}
Python
\u25FC
Ruby
\u{25fc}
Rust
\u{25fc}
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