iterated function left-composition with self: f∘f∘...∘f, n times.
First argument must be a function(al) or some object f that can be left-composed with itself (and which is unary); second argument is a real number (usually nonnegative integer) n for which n compositions of f makes sense; the result is f left-composed with itself n times and, as such, is itself a function(al) or other object of the same sort as f (therefore, it can then be applied to an m-tuple input, where m is less than or equal to the arity of f; if f is a function, then the output will generally not be a number in the codomain of f, but rather a function itself). This word is a shortcut for longer expressions. See also: fa'ai, se'au, te'a, fe'a.