Definition
Binomial coefficient
Also known as: n choose k, combinations
A count of how many ways you can choose k items from a set of n, when the order does not matter. Read aloud as "n choose k", it answers questions like how many different ways there are to get exactly k heads in n coin flips. For 10 flips, there are 252 ways to land exactly five heads, which is why that outcome is the most common.