Scales are often abstracted from performance or composition, though they are often used precompositionally to guide or limit a composition.
Scales in traditional Western music generally consist of seven notes, made up of a root note and six other scaledegrees whose pitches lie between the root and the root's first octave.
The notes in a chord are usually a subset of a particular scale, in the common practice period being built upward by thirds from a particular scaledegree.