noun
dwarf planet
Astronomical term for a celestial body that orbits the sun and has sufficient mass for a nearly round shape, but has not cleared its neighboring region. Compare with 準惑星 (じゅんわくせい), which is the more common term in modern Japanese.
See also: 準惑星
冥王星は矮惑星に分類されている。
Pluto is classified as a dwarf planet.
準惑星 is the more common and standard term for 'dwarf planet' in modern Japanese. 矮惑星 is a less frequent synonym, with 矮 meaning 'dwarf' or 'small'.
Compound of 矮 (わい, 'dwarf, small') and 惑星 (わくせい, 'planet'). The kanji 矮 is relatively rare and carries the meaning of 'short' or 'small in stature', used here in a technical astronomical sense.