Raawr is a word commonly used to refer to the sound dinosaurs make. So technically seen it's an onomatopeia. It is nearly the same as 'rawr', the word it originally descended from, which is spelled with one 'a'. Raawr can have different definitions in Dinosaur; some examples below.
Raawr = 'I'm hungry'
Raawr = 'I love you'
Raawr = 'I eat you'

Raawr is not only used by dinosaurs, but also by really big cats and some boys and girls among us. It would not really be the same though, as when said by a dinosaur or a big kitty it might just be more intimidating. So don't worry too much about it if your girlfriend says 'raawr' to you. She's probably not hungry. But she might just eat you.
Dinosaur: Raawr!
Anybody else: Eek! Halp! OhmaiGod! A dinosaur! *flee*
Dinosaur: ...

Girl: Raawr! <333.
Boy: ?!
by Lolhammy July 12, 2009
Get the Raawr mug.
"I Love You" in dinosaur.
sometimes used an an act of agression.
Girl: RAAWR .. <3
Boy: ????
by (: SMILE :) November 28, 2008
Get the RAAWR mug.
Often accompanied with a question mark
"Raawr ?"

Can be used to define one of two things, either utter distatse, OR in a playful mood making someone feel better or to cause laughter.
BOB: Raawr ?
CLAIRE: WTF ?
BOB: Raawr ??
CLAIRE: Rofl !
by Druchii February 14, 2005
Get the raawr mug.