Yes, the expression $x - \frac{1}{3}$ is a polynomial.

A polynomial is an algebraic expression consisting of variables and constants, combined using addition, subtraction, multiplication, and non-negative integer exponents of variables. The expression $x - \frac{1}{3}$ fits this definition. It can be rewritten as:

$x - \frac{1}{3} = \frac{3x - 1}{3}$

Even though it can be written as a fraction, the expression itself is a linear polynomial of degree 1, with the general form $ax + b$, where $a = 1$ and $b = -\frac{1}{3}$.

Would you like more details or have any further questions?

Here are some related questions you might find useful:

1. What is the degree of a polynomial?
2. How can you classify polynomials based on their degree?
3. Can a polynomial have fractional coefficients?
4. What are the differences between polynomials and rational expressions?
5. How do you factor linear polynomials?

Tip: When determining if an expression is a polynomial, ensure that the exponents of the variables are non-negative integers and that the operations involved are only addition, subtraction, and multiplication.