A spherical cloud of small rocky and icy bodies postulated to orbit the sun beyond the orbit of Pluto and up to 1.5 light years from the sun, and to act as a reservoir of comets. Its existence was proposed by J. H. Oort.
Definition of Oort cloud in US English:
Oort cloud
proper noun
Astronomy
A spherical cloud of small rocky and icy bodies postulated to orbit the sun beyond the orbit of Pluto and up to 1.5 light years from the sun, and to be the source of comets. Its existence was proposed by J. H. Oort.