 Order of a zero of a differential

If a local holomorphic $r$-differential is $z^{m}u(z)d{z}^r$, where $u(0)\ne 0$, its zero order is $m$. The order is unchanged by a holomorphic coordinate change with nonzero derivative. For a holomorphic one-form the cone angle is $2\pi (m+1)$, and for a holomorphic quadratic differential it is $(m+2)\pi$.