A trinomial is a type of polynomial that consists of three terms. These terms are typically separated by addition or subtraction operators. For example, the expression x^2 + 5x + 6 is a trinomial because it has three distinct parts: x^2, 5x, and 6. Trinomials can be used in various mathematical contexts, including algebra and calculus. Trinomials can often be factored into simpler expressions, which is useful for solving equations. For instance, the trinomial x^2 + 5x + 6 can be factored into the product of two binomials: (x + 2)(x + 3). Understanding trinomials is essential for students learning algebra, as they form the basis for more complex mathematical concepts.