A binomial is a mathematical expression that consists of two terms separated by a plus or minus sign. For example, in the expression 3x + 5, the two terms are 3x and 5. Binomials can be used in various mathematical operations, including addition, subtraction, and multiplication. In algebra, binomials are often used in polynomial equations and can be factored or expanded. The Binomial Theorem provides a formula for expanding binomials raised to a power, making it easier to work with these expressions in higher-level mathematics.