Naming suggestion for this particular delegate/function

[Bruno Medeiros]

Consider the familiar functional idiom "map" 
(http://en.wikipedia.org/wiki/Map_%28higher-order_function%29)

What would you call such a function parameter (either for map or just 
generally). That is, what would you call a function that takes one 
parameter of some type, and produces another object/data from that input?
Is there any usual name/term for this, I wonder, or not really?

-- 
Bruno Medeiros - Software Engineer