The Collaborative International Dictionary of English v.0.48:
Planetoid \Plan"et*oid\, n. [Planet + -oid.] (Astron.) A body resembling a planet; an asteroid. [1913 Webster]WordNet (r) 3.0 (2006):
planetoid n 1: any of numerous small celestial bodies that move around the sun [syn: minor planet, planetoid]