a planet that scientists hypothesize is found beyond pluto. we cannot see it due to our meek scientific technology. there are cosmic radiation signals or something being emitted that make other planets orbit right or something like that that pluto cannot cause, so therefore there must be another planet doing it.
"we will one day find planet x"- some scientist.
by thegreatmonkey February 14, 2005

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Top Definition
A mystical planet that is apparently supposed to crash into earth on December 21st, 2012. Although there is no proof, people are still scared shitless because of this.
Planet X: IM COMING FOR U EARTH!
Brasil: NUU men plis attack europe!
Europe: TALLEY HO! ATTACK MEXICO!
Mexico: Si?
by TacoMann May 25, 2009

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the t-shirt

The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt