1. (noun) a recurring sleep state during which dreaming occurs; a state of rapidly shifting eye movements during sleep

• paradoxical sleep
• rapid eye movement
• rapid eye movement sleep
• rem sleep

1. (noun) a recurring sleep state during which dreaming occurs; a state of rapidly shifting eye movements during sleep

• sleep
• slumber

2. (noun) (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

• radioactivity unit