What does Oort cloud mean?
• OORT CLOUD (noun) The noun OORT CLOUD has 1 sense: 1. (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 Familiarity information: OORT CLOUD used as a noun is very rare.