Code point
U+22EF
Glyph appearance depends on your fonts.
U+22EF
SmU+22EF MIDLINE HORIZONTAL ELLIPSIS is a Unicode 16.0.0 character in the Math Symbol category. It belongs to the Mathematical Operators block.
Choose the representation you need, then copy its value.
U+22EF
8943
⋯
⋯
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E2 8B AF
22EF
000022EF
%E2%8B%AF
\u22EF
\u22EF
\u22EF
\22EF