We know that a polynomial having only one term is called a monomial, a polynomial having only two terms is called binomial, a polynomial having only three terms is called a trinomial.

$(i)$ $3 x$ is monomial of degree $1 .$

$(ii)$ $x^{20}-7$ is a binomial of degree $20 .$

$(iii)$ $5 x^{2}+3 x-1$ is a trinomial of degree $2 .$