Dione

1 of 2

noun

Di·​o·​ne ˌdī-ˈō-nē 

astronomy

: 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

-dione

2 of 2

noun suffix

-di·​one

ˈdīˌōn

plural -s

: chemical compound containing two carbonyl groups

—in names of diketones or di-oxo compounds that are not true diketones

butanedione

2,6-piperidine-dione

Word History

Etymology

Noun suffix

International Scientific Vocabulary di- + -one

First Known Use

Noun

1879, in the meaning defined above

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