Answer
The given expression is a polynomial of degree $3$.
Work Step by Step
A monomial is an expression of the form $ax^{k}$,
where $x$ is the variable,
the exponent $k$, a nonnegative integer, is the degree,
and $a$ is the coefficient of the term.
A polynomial expression is either a single monomial or a SUM of several monomials.
The degree of the polynomial is the degree of the monomial with the highest degree.
$2y^{3}$ is a monomial of degree $3$,
$-\sqrt{2}=-\sqrt{2}\cdot y^{0}$ so it is a monomial of degree $0$
Their sum is a polynomial (a binomial).
This is a polynomial of degree 3.
