Oort Cloud Definition

ôrt

noun

A spherical, moving mass of icy cosmic debris thought to exist in the vast region beyond Pluto and to be the source of the long-period comets that orbit the sun.

Webster's New World

pronoun

(astronomy) A roughly spherical region of space from 50,000 to 100,000 astronomical units (approximately 1 light year) from the sun; supposedly the source of most comets.

Wiktionary

Other Word Forms of Oort Cloud

Noun

Singular:

Oort cloud

Plural:

Oort clouds

Origin of Oort Cloud

After Jan Hendrix Oort (1900–1992), Dutch astronomer

From American Heritage Dictionary of the English Language, 5th Edition
Named after Dutch astronomer Jan Hendrik Oort.

From Wiktionary