The Collaborative International Dictionary of English v.0.48:

Taffrail \Taff"rail\, n. [D. tafereel a panel, picture, fr.
   tafel table, fr. L. tabula. See Table.] (Naut.)
   The upper part of a ship's stern, which is flat like a table
   on the top, and sometimes ornamented with carved work; the
   rail around a ship's stern. [Written also tafferel.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

taffrail
    n 1: the railing around the stern of a ship