Heterochromia.
I would have been even more impressed if you had come up with the word for different coloured ears!
@FrayedBear Would you settle for genetic anomaly. How about Audiomytosis! Only so many tricks can be pulled out of the magic linguistic hat. Enjoy your day.
@PaddyO I shall enjoy this exceptionally cool day - 21°C in mid summer is a relief after upper 30's. But today has been enhanced by someone contacting me to ask if I'll look after their cherished 3 dogs & a cat for 6 weeks in N.Adelaide. Quite a fillip. Just hope that I live that long!