The Collaborative International Dictionary of English v.0.48:

Fratercula \Fratercula\ n.
   a genus of sea birds, one of the genera of puffins.

   Syn: genus Fratercula.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Fratercula
    n 1: puffins [syn: Fratercula, genus Fratercula]