The Collaborative International Dictionary of English v.0.48:

Sporades \Spor"a*des\ (sp[o^]r"[.a]*d[=e]z), n. pl. [L., fr. Gr.
   spora`des. Cf. Sporadic.] (Astron.)
   Stars not included in any constellation; -- called also
   informed, or unformed, stars.
   [1913 Webster]