  Tropical roots of tropical polynomials have been previously studied and used
to localize roots of classical polynomials and eigenvalues of matrix
polynomials. We extend the theory of tropical roots from tropical polynomials
to tropical Laurent series. Our proposed definition ensures that, as in the
polynomial case, there is a bijection between tropical roots and slopes of the
Newton polygon associated with the tropical Laurent series. We show that,
unlike in the polynomial case, there may be infinitely many tropical roots;
moreover, there can be at most two tropical roots of infinite multiplicity. We
then apply the new theory by relating the inner and outer radii of convergence
of a classical Laurent series to the behavior of the sequence of tropical roots
of its tropicalization. Finally, as a second application, we discuss
localization results both for roots of scalar functions that admit a local
Laurent series expansion and for nonlinear eigenvalues of regular matrix valued
functions that admit a local Laurent series expansion.
