jiǎ zǐ
first year of the sixty-year cycle (where each year is numbered with one of the 10 heavenly stems 天干[tian1 gan1] and one of the 12 earthly branches 地支[di4 zhi1])
the sixty-year cycle
甲
jiǎ
first of the ten Heavenly Stems 十天干[shi2 tian1 gan1]
子
zǐ
son