first of the ten Heavenly Stems 十天干[shi2 tian1 gan1] / (used for an unspecified person or thing) / first (in a list, as a party to a contract etc) / letter "A" or roman "I" in list "A, B, C", or "I, II, III" etc / armor plating / shell or carapace / (of the fingers or toes) nail / bladed leather or metal armor (old) / ranking system used in the Imperial examinations (old) / civil administration unit in the baojia 保甲[bao3 jia3] system (old) / ancient Chinese compass point: 75°