noun
binomial coefficient
A mathematical term for the coefficient of a term in the expansion of a binomial power, often written as nCk or (n choose k).
二項係数は組み合わせの数を表すのによく使われる。
Binomial coefficients are often used to represent the number of combinations.
二項定理 (binomial theorem) is the theorem that describes the expansion of a binomial, while 二項係数 refers specifically to the coefficients in that expansion.
Compound of 二項 (binomial) and 係数 (coefficient). The term is a direct translation of the English mathematical term 'binomial coefficient'.