NOUN (2)

1. a form of Japanese poetry; the 1st and 3rd lines have five syllables and the 2nd, 4th, and 5th have seven syllables;

2. a Tibetan religious painting on fabric;

The Collaborative International Dictionary of English v.0.48:

Tanka \Tan"ka\, n. (Naut.)
   A kind of boat used in Canton. It is about 25 feet long and
   is often rowed by women. Called also tankia. --S. W.
   Williams.
   [1913 Webster]

WordNet (r) 3.0 (2006):

tanka
    n 1: a form of Japanese poetry; the 1st and 3rd lines have five
         syllables and the 2nd, 4th, and 5th have seven syllables
    2: a Tibetan religious painting on fabric