Audio: key (0:08)
key plays a melody on an overdriven (distorted) guitar in the key of E phrygian. The key figure shows that the melody in the score uses all the notes in the key of E phrygian. E, the tonic note, starts the melody, ends the melody, starts each bar, and is played six times in total, more than any other note. The key table lists the degree number and name of each note in a scale.
A key is a scale with a named tonic note.
A degree is the name or number of a note in a scale.
The tonic is the first note in a scale.
A key has two parts: a tonic and a scale. The first part is the name of the tonic note. The second part is the name of the scale. Taken together the name of the tonic note and the name of the scale uniquely identify the key of a piece of music.
C major is a key. It is probably the most popular key in music. The tonic note is C and the scale is a major scale. The major scale is such a familiar scale that the word, major, is often omitted and the key of C is shorthand for the key of C major.
A degree is the name or number of a note in a scale. Every note in a scale has a name or a number. Numbering starts at one, the tonic, and proceeds upwards to the seventh degree, the leading note. The names are a bit obscure but they are widely used to describe the degree.
A tonic is not a pick-me-up tonic but a note name. The tonic is A, D, Gb or whichever note you select to be the first note in a scale. An ascending scale increases in pitch from the tonic up to whatever note is the last note in that scale, a descending scale reduces in pitch from the tonic.
The tonic is the most important note in a key. A piece of music often starts and ends on the tonic and returns to it at regular intervals. A tonic often appears at the beginning of a bar to automatically accent it and emphasise its importance.
Tonal music has a key, atonal music does not.