A bilinear pairing is a function $e$ that takes two arguments and returns a single value. Arguments and return values belong to (possibly distinct) groups with inputs written additively and outputs written multiplicatively. The function is linear in both arguments so that $e(a+b,c)=e(a,c)e(b,c)$ and $e(a,c+d)=e(a,c)e(a,d)$.
A bilinear pairing is a function $e$ that takes two arguments and returns a single value. Arguments and return values belong to (possibly distinct) groups with inputs written additively and outputs written multiplicatively. The function is linear in both arguments so that $e(a+b,c)=e(a,c)e(b,c)$ and $e(a,c+d)=e(a,c)e(a,d)$. An example is the Weil pairing for elliptic curves.