Rondel
Rondel , noun
1.
(Fortification) A small round tower erected at the foot of a bastion. [Obsolete]
2.
(a) Same as Rondeau.
(b)
Specifically, a particular form of rondeau containing fourteen lines in two rhymes, the refrain being a repetition of the first and second lines as the seventh and eighth, and again as the thirteenth and fourteenth. — E. W. Gosse