Rare, old-fashioned word for a meteorite; the common modern term is 隕石 (いんせき). The kanji 星屎 literally means 'star excrement'.
See also: 隕石
In old documents, the word 星屎 sometimes appears meaning meteorite.
Kana spelling is practical for this rare word, avoiding the obscure kanji.
Compound of 星 (ほし, 'star') and 屎 (くそ, 'excrement'), literally 'star excrement'. The exact historical derivation is uncertain; the spelling is conventionally associated with the meaning 'meteorite'.