1) just define function a binary function:
{def power {lambda {:a :b} {pow :a :b}}}
-> power

2) and use it:
{power 2 8}                            // power is a function waiting for two numbers
-> 256

{{power 2} 8}                          // {power 2} is a function waiting for the missing number
-> 256

{S.map {power 2} {S.serie 1 10}}       // S.map applies the {power 2} unary function
-> 2 4 8 16 32 64 128 256 512 1024     // to a sequence of numbers from 1 to 10