tan·ka 1 
(tängkə)
(tängkə)n.
1.
a. A Japanese lyric verse form having seven unrhymed lines, the first and third composed of five morae and the rest of seven.
b. A verse form in another language modeled on the Japanese tanka, typically counting syllables instead of morae.
2. A poem written in such a form.
[Japanese : tan, short (from Middle Chinese tuan´; also the source of Mandarin duǎn) + ka, song, poem (from Middle Chinese ka; also the source of Mandarin gē).]