矮わい惑わく星せいわいわくせいMeanings1noundwarf planetastronomy›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: 準惑星冥めい王おう