In mathematics, an algebroid function is a solution of an algebraic equation whose coefficients are analytic functions. So y(z) is an algebroid function if it satisfies

${\displaystyle a_{d}(z)y^{d}+\ldots +a_{0}(z)=0,}$

where ${\displaystyle a_{k}(z)}$ are analytic. If this equation is irreducible then the function is d-valued, and can be defined on a Riemann surface having d sheets.