Key Signature

A key signature represents the sharps & flats in a particular key. Each key signature represents one major key, and one minor key (“relative” keys). For example, C major and A minor (no key signature, because there are no sharps or flats).

X:1
T:D major
K:D
L:1/8
]

Key

A key is the collection of notes that form the basis of a musical composition.

Keys feature a tonic note and its corresponding tonic or tonic chord.

A key can be in either the major or minor mode.

Key & Scale

A Scale is the set of ordered notes in a key. The key is the “center of gravity” of the notes.