clockwise順時針
coefficient系數
column列,圓柱
common denominator公分母
common difference等差數列的公差
common divisor(factor)共因子;公約數
common ratio等比數列的公比
common multiple公倍數
complement余角
complementary angle余角
complete circle全圓
complete quadratic (equation)全二次方程
complex fraction繁分數