The Collaborative International Dictionary of English v.0.48:

Orderer \Or"der*er\, n.
   1. One who puts in order, arranges, methodizes, or regulates.
      [1913 Webster]

   2. One who gives orders.
      [1913 Webster]

WordNet (r) 3.0 (2006):

orderer
    n 1: someone who places an order to buy
    2: an organizer who puts things in order; "Aristotle was a great
       orderer of ideas" [syn: orderer, systematizer,
       systematiser, systemizer, systemiser, systematist]