A polynomial is a mathematical expression that has two or more terms. It can be made up of numbers, variables, and operations like addition, subtraction, multiplication, and division. The terms can also contain exponents, like x^2, which means x raised to the power of 2.

Think of it like building with blocks. A polynomial is like a building made up of many blocks. Each block is a term, and the terms can have different numbers and letters on them, like x^2 or 5x. The terms can also have different operations between them, like + or -.

For example, "3x^2 + 2x + 1" is a polynomial because it has three terms: "3x^2", "2x", and "1". Each term has a different number and letter, and the terms are connected by addition and subtraction operations.

So, a polynomial is a mathematical expression that has two or more terms. It can be made up of numbers, variables, and operations, and can also contain exponents. It's like a building made up of many blocks, where each block is a term.