<!--
{
  "availability" : [
    "iOS: 27.0.0 -",
    "iPadOS: 27.0.0 -",
    "macCatalyst: -",
    "macOS: 27.0.0 -",
    "tvOS: 27.0.0 -",
    "visionOS: 27.0.0 -",
    "watchOS: 27.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "MusicUnderstanding",
  "identifier" : "/documentation/MusicUnderstanding/KeyResult/Tonic",
  "metadataVersion" : "0.1.0",
  "role" : "Enumeration",
  "symbol" : {
    "kind" : "Enumeration",
    "modules" : [
      "Music Understanding",
      "MusicUnderstanding"
    ],
    "preciseIdentifier" : "s:18MusicUnderstanding9KeyResultV5TonicO"
  },
  "title" : "KeyResult.Tonic"
}
-->

# KeyResult.Tonic

The root note of a musical key.

```
@frozen enum Tonic
```

## Topics

### Enumeration Cases

[`case a`](/documentation/MusicUnderstanding/KeyResult/Tonic/a)

Indicates that the song is in an A key.

[`case aFlat`](/documentation/MusicUnderstanding/KeyResult/Tonic/aFlat)

Indicates that the song is in an A-flat key.

[`case aSharp`](/documentation/MusicUnderstanding/KeyResult/Tonic/aSharp)

Indicates that the song is in an A-sharp key.

[`case b`](/documentation/MusicUnderstanding/KeyResult/Tonic/b)

Indicates that the song is in a B key.

[`case bFlat`](/documentation/MusicUnderstanding/KeyResult/Tonic/bFlat)

Indicates that the song is in a B-flat key.

[`case c`](/documentation/MusicUnderstanding/KeyResult/Tonic/c)

Indicates that the song is in a C key.

[`case cSharp`](/documentation/MusicUnderstanding/KeyResult/Tonic/cSharp)

Indicates that the song is in a C-sharp key.

[`case d`](/documentation/MusicUnderstanding/KeyResult/Tonic/d)

Indicates that the song is in a D key.

[`case dFlat`](/documentation/MusicUnderstanding/KeyResult/Tonic/dFlat)

Indicates that the song is in a D-flat key.

[`case dSharp`](/documentation/MusicUnderstanding/KeyResult/Tonic/dSharp)

Indicates that the song is in a D-sharp key.

[`case e`](/documentation/MusicUnderstanding/KeyResult/Tonic/e)

Indicates that the song is in an E key.

[`case eFlat`](/documentation/MusicUnderstanding/KeyResult/Tonic/eFlat)

Indicates that the song is in an E-flat key.

[`case f`](/documentation/MusicUnderstanding/KeyResult/Tonic/f)

Indicates that the song is in an F key.

[`case fSharp`](/documentation/MusicUnderstanding/KeyResult/Tonic/fSharp)

Indicates that the song is in an F-sharp key.

[`case g`](/documentation/MusicUnderstanding/KeyResult/Tonic/g)

Indicates that the song is in a G key.

[`case gFlat`](/documentation/MusicUnderstanding/KeyResult/Tonic/gFlat)

Indicates that the song is in a G-flat key.

[`case gSharp`](/documentation/MusicUnderstanding/KeyResult/Tonic/gSharp)

Indicates that the song is in a G-sharp key.

## Relationships

### Conforms To

[`Equatable`](/documentation/Swift/Equatable)

[`Copyable`](/documentation/Swift/Copyable)

[`Hashable`](/documentation/Swift/Hashable)

[`BitwiseCopyable`](/documentation/Swift/BitwiseCopyable)

[`RawRepresentable`](/documentation/Swift/RawRepresentable)

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

[`Escapable`](/documentation/Swift/Escapable)

[`Encodable`](/documentation/Swift/Encodable)

[`Sendable`](/documentation/Swift/Sendable)

[`Decodable`](/documentation/Swift/Decodable)

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)