Definition

1. Noun:
   • A unit of measurement for ionizing radiation dosage: The "rem" (Roentgen Equivalent Man) quantifies the biological effect of radiation exposure on human tissue. One rem represents the amount of radiation that produces the same biological damage as one roentgen of high-voltage X-rays.
   • A stage of sleep characterized by rapid eye movement: The "REM" (Rapid Eye Movement) is a recurring phase of the sleep cycle during which dreaming typically occurs, marked by heightened brain activity and rapid, random movements of the eyes.

Usage Examples

• Noun (Radiation Unit):

  • The safety guidelines limit occupational exposure to five rem per year.
  • The patient received a dose of 0.1 rem from the diagnostic X-ray.

• Noun (Sleep Stage):

  • Most vivid dreams happen during REM sleep.
  • The sleep study showed he was entering the REM phase approximately 90 minutes after falling asleep.

Advanced Usage

• "rem sleep": This is the standard compound term for the sleep stage. While "REM" is the acronym, "rem" is commonly used in lowercase in this context.
  • Babies spend a much larger proportion of their sleep in rem sleep than adults do.

Variants and Related Words

• Millirem (mrem) (n): A unit equal to one-thousandth of a rem, used for smaller radiation doses.
  • The background radiation level is about 300 millirem per year.
• Non-REM sleep (n): The collective stages of sleep that are not characterized by rapid eye movement.
  • The body repairs itself primarily during non-REM sleep.

Synonyms

• For Radiation Unit: There is no direct synonym, as it is a specific unit. Related terms include sievert (Sv) (the modern SI unit, where 1 Sv = 100 rem) and rad (a unit of absorbed dose).
• For Sleep Stage: Rapid eye movement sleep, paradoxical sleep, dream sleep.

Related Phrases

• REM atonia: The state of muscle paralysis that normally occurs during REM sleep to prevent acting out dreams.
  • REM atonia is essential for preventing injury during vivid dreams.
• REM rebound: The phenomenon of increased REM sleep following a period of REM deprivation.
  • After staying awake all night, he experienced significant REM rebound.

Noun

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