Real Dictionary

rondel in American English
a kind of rondeau, usually with fourteen lines, two rhymes, and the first two lines used as a refrain in the middle and at the end (the second line occasionally being omitted at the end)
noun: a short poem of fixed form, consisting usually of 14 lines on two rhymes, of which four are made up of the initial couplet repeated in the middle and at the end, with the second line of the couplet sometimes being omitted at the end

rondel in British English
noun: a rondeau consisting of three stanzas of 13 or 14 lines with a two-line refrain appearing twice or three times