Each scale has seven tones (eight, if you include the octave). There are two ways to talk about tones: by number and by degree.
Scale Tones by Number
In a C major scale, the note C is given the number one because it's the first note of the scale. Then, each of the scale tones, one through seven, can be assigned a different note. This is useful for several reasons. First, the distance of an interval is measured with a number, which is often taken from a scale. Second, since all major scales are made of the same pattern, music theory uses a universal system for naming these scales. If a piece starts on the third note of a scale, you can take that idea and use it in any key. If you simply say, “It starts on E,” you lose the context of what scale or key you are in and need extra information in order to work with the idea. Using numbers is a handy way to think about scales and scale tones. A numbering system is also useful in the discussion of chords and chord progressions, since in music theory chord progressions are only labeled with Roman numerals.
Scale Tones by Degree
You can also describe the tones of the major scale by giving a name, instead of a number, to each degree. This method is traditionally used in classical or academic music-theory contexts, but some of the terms have become universal and you should at least be aware of them. One example is the term tonic, which is used to refer to the root (that is, the first chord or tone) of any scale. The chart below gives the names of each note in the major scale.
NAMES OF NOTES IN THE MAJOR SCALE
These names are also used when talking about chords and chord progressions, so knowing them will aid you in understanding progressions. Although these terms aren't used nearly as much as numbers for the tones, certain names such as tonic, dominant, and leading tone are prevalent in musicians’ vernacular. Formal theory, however, uses the names of scale degrees, so now you know what they mean.
Originating in the thirteenth century, the motet (derived from the French