In mathematics, a combination is a selection of items from a set that has distinct members, such that the order of selection does not matter (unlike permutations). For example, given three fruits, say an apple, an orange and a pear, there are three combinations of two that can be drawn from this set: an apple and a pear; an apple and an orange; or a pear and an orange. […] If the set has n elements, the number of k-combinations, denoted by \(C(n,k)\) or \(C_{k}^{n}\), is equal to the binomial coefficient [Binomial coefficient].

(“Combination” 2023)

To restate the example above of the orange, pear, and apple using the Binomial coefficient: \(\binom{3}{2} = 3\).

Also see: Permutation