---
title: KeyResult.Tonic.a
framework: musicunderstanding
role: symbol
role_heading: Case
platforms: [iOS 27.0+, iPadOS 27.0+, Mac Catalyst 27.0+, macOS 27.0+, tvOS 27.0+, visionOS 27.0+, watchOS 27.0+]
path: musicunderstanding/keyresult/tonic/a
---

# KeyResult.Tonic.a

Indicates that the song is in an A key.

## Declaration

```swift
case a
```