The Collaborative International Dictionary of English v.0.48:
Brioche \Bri`oche"\, n. [F.] 1. A light sweet pastry (cake, bun or roll) made with flour, butter, yeast, and eggs. [Webster 1913 Suppl.] 2. A knitted foot cushion. [Webster 1913 Suppl.]WordNet (r) 3.0 (2006):
brioche n 1: a light roll rich with eggs and butter and somewhat sweet