What 🏲 means
It names a pennant-shaped flag; its use supplies the message. A pennant is a narrow flag that tapers to a point. English naval records describe signal banners by about 1338, without specifying a black design. Dutch royal practice used a black pennant for mourning at a funeral in 1879 and again after 11 September 2001.
For a black pennant weather signal, placement mattered: a 1893 U.S. Weather Bureau chart used a pennant above or below a flag marking rain or snow to indicate warmer or colder weather. A Sydney naval display used the same position-based reading in 1931. As a text glyph, its outline comes from the font, so its appearance can vary by device.
Solemn in mourning contexts; elsewhere, cryptic unless the context is clear.
Alone, it is too ambiguous for condolences; the mourning convention may be missed.
Don't confuse it with
1Questions 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 🏲
🏲\1F3F2Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.