∎
Definition from Wiktionary, the free dictionary
See also: ■ [U+25A0 BLACK SQUARE]
Character  ∎  

Unicode name  END OF PROOF  
Code point  U+220E  
Unicode block  Mathematical Operators  
LaTeX input  \blacksquare 


Translingual[edit]
Etymology[edit]
Introduced into mathematical usage by Paul Halmos, modeled after the end sign ■ (a printer’s ornament or dingbat used to indicate the end of an article or story) found in popular print media.
Symbol[edit]
∎
 (mathematics) QED.
Usage notes[edit]
The symbol itself is called a tombstone or halmos in English.