trans-Neptunian object

or trans·nep·tu·ni·an ob·ject

[ trans-nep-too-nee-uhn ob-jikt, ‐jekt, ‐-tyoo‐, tranz ]

noun

, Astronomy.

1. any celestial object in our solar system whose orbit lies beyond Neptune, including Pluto: there may be some 70,000 trans-Neptunian objects orbiting 30–50 astronomical units from the sun, with diameters of at least 62 miles (100 km). : TNO

trans-Neptunian object

/ trăns′nĕp-to̅o̅n′ē-ən /

1. A celestial object that orbits the sun at a greater distance on average than Neptune.

Word History and Origins

Origin of trans-Neptunian object¹

First recorded in 1920–25