It is clearly a word derived from music, where its meaning is more definite. We speak of a piano’s tone, by which we mean that, though it sounds the same notes as another piano, the quality of the sounds differs. We shall be using the word quality often in the present chapter, so let us be sure we understand its meaning. It is from the Latin word _qualis_, which means of what kind. Of what kind is this piece of dress goods; what is its quality, compared with another piece, at first sight similar? Is it all wool, for example, while the other is cotton mixture? Is it softer, while the other is harder and drier? Will the one stand washing, while the other will shrink? Similarly, when the same note is struck on two pianos the tone of one may be rich, mellow, resonant, while that of the other is thin, raw, and metallic.