Yes, rems is a Scrabble word!
...and is worth 6 points in Scrabble, and 7 points in Words with Friends
rems
Noun
1. A recurring sleep state during which dreaming occurs; a state of rapidly shifting eye movements during sleep
2. (Roentgen Equivalent Man) the dosage of ionizing radiation that will cause the same amount of injury to human tissue as 1 roentgen of X-rays
What Scrabble words can I make with the letters in rems?
3 Letter Words
2 Letter Words