What ⬫ means
The shape is centuries old; this character has its own history.
A 1911 encyclopedia describes the shape on heraldic shields and records lozenge patterns as popular decoration in the 14th century.
A separate computer-era symbol, ◊, appeared in Macintosh and PostScript sets. Its PostScript trail reaches a 1985 manual for describing printed pages; Macintosh references showed ◊ as an open diamond in 1985, then more like a lozenge by 1993.
A quiet typographic marker: it reads as layout or decoration more readily than as emotion.
Don't confuse it with
3Questions people ask
1Why does ⬫ show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type ⬫
⬫\2B2BCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.