26:2 · An empty circle that is considerably smaller than most of the other signs in a given ideographic system has a spectrum of meaning that focuses on the idea of something small or weak. It often means a small part of a larger unit that is divided into even parts. Thus it is used to represent degrees when measuring temperature and when dividing a circle.
    In music and phonetics is used to indicate weak tones and toneless sounds, and in some meteorological systems it has been used for low intensity about weather conditions. In books about mushrooms it is often used for edible after parboiling.