I think you could make a palindrome starting with with "Un balun y un unun..." I don't think I'm the right man for that task. But I can tell you what they are and what they are for. balun is a difficult word to research being both a surname, an engineering term, a city, and a slang word in Spanish meaning balloon. They are both types of transformers and sometime I'll have to write a post about those as well.
- Balun [bal-uhn] noun
Very High-Frequency Techniques, Vol. 1 - Harvard U. - 1947
"For a fixed position of the balun short-circuiting bar, the induced voltage E tends to increase with the frequency"
Hewlett-Packard Journal , Volumes 1-13 - H.P. Company - 1949
"When this condition exists, there is theoretically no phase error introduced by deviations in balun legnth."
Radio Engineering - Terman, Frederick- Mcgraw-Hill - 1947
"At the same time, the balun does not introduce an unbalanced load to the balanced system, since the impedance across 2-3 approaches infinity..."
- Unun [uhn-uhn] noun