The Binomial Theorem provides a formula to expand any binomial expression raised to a positive integer power. It expresses the expansion as a sum involving terms of the form $a^k b^{n-k}$ multiplied by binomial coefficients.
Factorial: The product of all positive integers up to a given number n, denoted by n!. For example, $5! = 5 \times 4 \times 3 \times 2 \times 1 = 120$.
Pascal's Triangle: A triangular array of numbers where each number is the sum of the two directly above it. It represents binomial coefficients.
Binomial Coefficient: $\binom{n}{k}$ represents the number of ways to choose k elements from an n-element set. Calculated as $\frac{n!}{k!(n-k)!}$.