epicycle
Concise Oxford English Dictionary © 2008 Oxford University Press:
epicycle /ˈɛpɪˌsʌɪk(ə)l/
▶noun Geometry a small circle whose centre moves round the circumference of a larger one.
– derivatives
epicyclic adjective.
epicyclic adjective.
– origin ME: from OFr., or via late L. from Gk epikuklos.
'epicycle' also found in these Oxford entries:

