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 2x^2 + 3x - 5 is a trinomial because it has three distinct parts: 2x^2, 3x, and -5. Trinomials can be used in various mathematical contexts, including algebra and calculus. Trinomials can often be factored into the product of two binomials. For instance, the trinomial x^2 + 5x + 6 can be factored into (x + 2)(x + 3). Understanding trinomials is essential for solving quadratic equations and is a foundational concept in algebra, which is a branch of mathematics that deals with symbols and the rules for manipulating those symbols.