The Collaborative International Dictionary
Heteronymous
Heteronymous \Het`er*on"y*mous\, a. [Hetero- + Gr. "o`nyma, for
"o`noma a name.]
Having different names or designations; standing in opposite
relations.
--J. Le Conte. -- Het"er*on"y*mous*ly, adv.
Wiktionary
heteronymous
a. 1 Of, or relating to a heteronym 2 Being different words, but having a common relationship e.g. brother and sister are siblings of each other