U+1D1A9 MUSICAL SYMBOL DEGREE SLASH

U+1D1A9 was added to Unicode in version 3.1 (2001). It belongs to the block Musical Symbols in the Supplementary Multilingual Plane.

This character is a Other Symbol and is commonly used, that is, in no specific script.

The glyph is not a composition. It has a Neutral East Asian Width. In bidirectional context it acts as Left To Right and is not mirrored. In text U+1D1A9 behaves as Alphabetic regarding line breaks. It has type Other for sentence and Other for word breaks. The Grapheme Cluster Break is Any.

The Wikipedia has the following information about this codepoint:

Various kinds of chord names and symbols are used in different contexts, to represent musical chords. In most genres of popular music, including jazz, pop, and rock, a chord name and the corresponding symbol are typically composed of one or more of the following parts:

1. The root note (e.g. C).
2. The chord quality (e.g. major, maj, or M).
3. The number of an interval (e.g. seventh, or 7), or less often its full name or symbol (e.g. major seventh, maj7, or M7).
4. The altered fifth (e.g. sharp five, or ♯5).
5. An additional interval number (e.g. add 13 or add13), in added tone chords.

For instance, the name C augmented seventh, and the corresponding symbol C^aug7, or C⁺⁷, are both composed of parts 1, 2, and 3.

Except for the root, these parts do not refer to the notes which form the chord, but to the intervals they form with respect to the root. For instance, C^aug7 indicates a chord formed by the notes C-E-G♯-B♭. The three parts of the symbol (C, aug, and 7) refer to the root C, the augmented (fifth) interval from C to G♯, and the (minor) seventh interval from C to B♭. A set of decoding rules is applied to deduce the missing information.

Although they are used occasionally in classical music, these names and symbols are "universally used in jazz and popular music", usually inside lead sheets, fake books, and chord charts, to specify the harmony of compositions. Other notation systems for chords include: plain staff notation, used in classical music, Roman numerals, commonly used in harmonic analysis, figured bass, much used in the Baroque era, and macro symbols, sometimes used in modern musicology.