rondel

n. [ Cf. Rondeau, Roundel. ] 1. (Fort.) A small round tower erected at the foot of a bastion. [ Obs. ] [ 1913 Webster ]

2. [ F. ] (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. [ 1913 Webster ]