Definition (elliptic function):

An elliptic function is a function ${\displaystyle f\in M(\mathbb {C} )}$ such that there exists a lattice ${\displaystyle L\subset \mathbb {C} }$ a basis ${\displaystyle \{w_{1},w_{2}\}}$ of which satisfies

${\displaystyle \forall z\in \mathbb {C} :f(z+w_{1})=f(z)=f(z+w_{2})}$.