Consider a complex torus $T=\mathbb{C}^n/L$ where $L$ is a discrete subgroup of $\mathbb{C}^n$. We say the torus $T$ carries a polarization $H$ if $H$ is a positive definite Hermitian form on $\mathbb{C}^n$ and $E: =\text{Im}\ H$ is an integer valued anti-symmetric form on $L$.
Why is the above Hermitian form $H$ called a polarization?