1. paradoxical sleep, rapid eye movement sleep, REM sleep, rapid eye movement, REM, sleep, slumber

usage: a recurring sleep state during which dreaming occurs; a state of rapidly shifting eye movements during sleep

2. REM, radioactivity unit

usage: (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

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See also: rem (Dictionary)