Top Definition
Noun- A hypothetical dinosaur large enough to swallow the sun. Also possibly the pet of Galactus.
1- "What happened to the sun, dude?"
"Oh, Galactasaurus Rex ate it."

2- "Yo, Andrew, what happens to planetary nebulas at the end of the Hertzsprung-Russell cycle?"
"I eat them. For I am Galactasaurus Rex. Muahahahahhahahaha!"
by Manish Melwani May 08, 2008
Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from We'll never spam you.