U+2421 SYMBOL FOR DELETE (␡)
Symbol For Delete is a Unicode character added in Unicode 1.1 from the Control Pictures block, being classified as an Other Symbol from no particular script. Its bidirectional class is Other Neutral and its combining class is Not Reordered. It has no mirrored or upper/lowercase variant and is not composed of other Unicode characters.
U+2682 DIE FACE-3 (⚂)
Die Face-3 is a Unicode character added in Unicode 3.2 from the Miscellaneous Symbols block, being classified as an Other Symbol from no particular script. Its bidirectional class is Other Neutral and its combining class is Not Reordered. It has no mirrored or upper/lowercase variant and is not composed of other Unicode characters.
U+1D209 GREEK VOCAL NOTATION SYMBOL-10 (𝈉)
Greek Vocal Notation Symbol-10 is a Unicode character added in Unicode 4.1 from the Ancient Greek Musical Notation block, being classified as an Other Symbol from the Greek script. Its bidirectional class is Other Neutral and its combining class is Not Reordered. It has no mirrored or upper/lowercase variant and is not composed of other Unicode characters.
This character was proposed by the Thesaurus Linguae Graecae Project, along with many other symbols found in their corpus. The musical notation was split into two parts, vocal and instrumental, each note from each part corresponding to a note in the other. These notes were also grouped in triads consisting of the natural, the first sharp, and the second sharp. Greek Vocal Notation Symbol-10 in particular was the vocal version of the natural modern A in the lowest octave.