Tonic

In Western music, the tonic is the main note of the scale and it is the pitch after which the key is named. For example, in C major or minor, C is both they name of the key and the tonic. Also, tonic can be defined as the first scale degree in a particular key. For example, Ab is the first degree in the key of Ab major or ab minor, followed by the supertonic which in this case would be Bb. Also, the word tonic can be used when talking about a tonic triad. A tonic triad is rooted in the first-scale degree and is usually the final chord in a piece of music according to Grove Music Online. The tonic is generally thought of as the root for the rest of the melody and harmony in Western music. In the 20th century, atonal music has gained a following with music that does not feel that it has a particular tonic pitch as other tonal music does.