ellipsoid
Concise Oxford English Dictionary © 2008 Oxford University Press:
ellipsoid /ɪˈlɪpsɔɪd/
▶noun a three-dimensional figure symmetrical about each of three perpendicular axes, whose plane sections normal to one axis are circles and all the other plane sections are ellipses.
– derivatives
ellipsoidal adjective.
ellipsoidal adjective.
'ellipsoid' also found in these Oxford entries:

