The Collaborative International Dictionary of English v.0.48:

coffeecake \cof"fee*cake`\ (k[add]"f[-e]*k[=a]`), n.
   a cake or sweet bread usually glazed after baking, and having
   added nuts and fruits; it is often served with coffee.

   Syn: coffee cake.
        [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

coffeecake
    n 1: a cake or sweet bread usually served with coffee [syn:
         coffeecake, coffee cake]