from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A swarm of comets orbiting the sun at a distance of one to two light-years, proposed as a source of comets that pass near the sun.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. (astronomy) a hypothetical huge collection of comets orbiting the sun far beyond the orbit of Pluto; perturbations (as by other stars) can upset a comet's orbit and may send it tumbling toward the sun
After Jan Hendrix Oort (1900-1992), Dutch astronomer.(American Heritage® Dictionary of the English Language, Fourth Edition)