Definition of Dione
(Entry 1 of 2)
: the fourth largest satellite of Saturn with a diameter of approximately 700 miles (1120 km) Three other new Saturnian moons have been identified in recent years by spacecraft and ground-based telescopes. Two of them are especially intriguing because they lie in essentially the same orbit about 94,000 miles from the planet. The third is a small, asteroid-size satellite moving along in the same orbit much farther ahead of the larger moon, Dione, 234,000 miles from Saturn.— John Noble Wilford, New York Times, 29 Oct. 1980
-di·one | \ ˈdīˌōn\
Definition of -dione (Entry 2 of 2)
: chemical compound containing two carbonyl groups —in names of diketones or di-oxo compounds that are not true diketones butanedione2,6-piperidine-dione
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