Si Collection, Lower Volume Radical: Cow (niú) Page 699, Entry 15 Pronounced si (falling tone). Shuowen Jiezi (Explaining Simple and Analyzing Compound Characters) defines this as a four-year-old ox. The character structure is composed of cow and four, with four also indicating the pronunciation. Guangya (Broad Refinement) also defines this as ferocious. In the Shuowen Jiezi, the seal script form is written as a variant form (zhòu).