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The Kuiper Belt (aka Edgeworth-Kuiper Belt or K Belt) is a region beyond Neptune (30-50 AU) with comets and minor planets (asteroid-like or somewhat comet-like). It was hypothesized over time, notably Kenneth Edgeworth in 1943 and Gerard Kuiper in 1951, and was clearly identified in 1992. Since then, over 1000 such objects have been discovered, and estimates are there could be 10,000, totaling 1/25 to 1/10 Earth masses. It includes objects more massive than does the asteroid belt. Unlike the much further distant Oort Cloud, the Kuiper Belt is somewhat flat, not extending so far from the ecliptic. The main part is within the region ranging from 2:3 to 1:2 orbital resonance with Neptune (40 to 48 AU), and many of the objects have little eccentricity. Others (such as Pluto) have orbits suggesting scattering, e.g., more eccentric and/or with some orbital inclination. Some are in families suggesting pasts breakups of larger bodies. Bodies in the Kuiper Belt are known as Kuiper Belt objects (K Belt objects, KB objects, KBOs, Edgeworth-Kuiper Belt objects or EKBOs). Among the largest:
Those with high eccentricity and/or inclination are sometimes termed extreme Kuiper Belt objects, abbreviated EKBO (or eKBO), obviously ambiguous as it also could be taken for Edgeworth-Kuiper Belt object. EKBOs include Sedna and 2012 VB113 (the latter nicknamed Biden). A classical Kuiper Belt object (or classical KBO or cubewano) has low eccentricity, is always beyond Neptune (unlike Pluto) and has no orbital resonance with Neptune. Examples: 2002 UX25, Varuna, 1992 OB1 (Albion), 2002 TX300, Quaoar, Huya, and 2002 AW197.
The term Exo-Kuiper Belt has been used for candidates for analogous belts around other stars.