In modern western music, a musical scale is a set of notes that form the fundamental basis of musical composition. The scale and key for a composition (or part of it) is the most important information you need to know, or to define.
In pop music, only two modes of scales are used:
- Major Scales
- Minor Scales
A scale is defined by its key and its mode. The key is the root note of the scale. Therefore, you call the key for a composition e.g. “C major”, “A# minor”.
The information of the scale and key is also called key signature. In sheet music, the key and mode is not expressed by text, but with sharp- and flat-signs on the staff. I do not cover this topic, there are good online references if you need to find the key from the signature on the staff.
Alternative Writings of the Scale and Key
The mode of a scale is not always spelled out, there are alternative ways to express it:
- A single uppercase note name, like A stands for a major scale.
- A minor scale is sometimes expressed by adding the lowercase letter m to the uppercase note name. The key Am means “A minor”.
- Sometimes, lowercase note names are used to express minor scales. If you find just “a” as key, it usually means “A minor”.