[jpsb]

Bingo! It is not a moon, since it does not orbit earth. This article is incorrect in describing Cruithne as a moon of earth's.

[RightWhale]

This article is incorrect in describing Cruithne as a moon of earth's.

Yes, it is a moon of earth. Not all orbits are round, other shapes are possible. Taking orbit as being somnething of a permanent, related, and periodic motion, a horseshoe orbit is a perfectly good orbit. If you want to just go around and around in a boring round orbit, take Lance Bass's seat on the Russian Soyuz rocket.