It's the10-letter term for the phrase"never oddor even"
[DOC] [TLE] Appendix:English palindromes - Wiktionary [PAR] This list includes some proper names, hyphenated words and archaic words, as 
well as ... Five letters; 1.1.7 Four letters; 1.1.8 Three letters; 1.1.9 Two letters; 1.1.