Rare, poetic or archaic term for 'planet', literally 'wandering star'. Modern Japanese uses 惑星 (わくせい) instead.
See also: 惑星
In old documents, planets are sometimes written as 迷い星.
Compound of 迷い (mayoi, 'wandering') + 星 (hoshi, 'star'), referring to the ancient observation that planets move against the fixed stars. The exact historical origin is uncertain.