# Definition
Let $f: D \to \mathbb{C}$ be a function with domain $D$.

We say that $f$ is **holomorphic** at $z_{0}$ if $f$ is [[Differentiable|differentiable]] in an [[Open Sets|open]] disk (entered at $z_{0}$).

> [!info] Remark on naming of "holomorphic"
> Many sources use the term **analytic** instead of holomorphic.