
1) Botanical nomenclature
Found on
https://www.crosswordclues.com/clue/isonym
[taxonomy] An isonym, in botanical taxonomy, is a name of a taxon that is identical to another designation, and based on the same type, but published at a different time by possibly different authors. Citation from that source follows: That is, the later isonyms are to be discarded, and only the first one is to be used, even though it may n...
Found on
http://en.wikipedia.org/wiki/Isonym_(taxonomy)

word having the same derivation or form as another
Found on
http://phrontistery.info/i.html

isonym, isonymous 1. A new name, of a species, etc., based on the same older name. 2. Having the same surname. 3. A word of the same derivation or form as another name.
Found on
http://www.wordinfo.info/words/index/info/view_unit/2565/6
No exact match found.