Rem vs. Sievert — What's the Difference?

The twitching movements of the eye muscles and other physiological changes that occur during REM sleep.

The sievert (symbol: Sv) is a derived unit of ionizing radiation dose in the International System of Units (SI) and is a measure of the health effect of low levels of ionizing radiation on the human body. The sievert is important in dosimetry and radiation protection, and is named after Rolf Maximilian Sievert, a Swedish medical physicist renowned for work on radiation dose measurement and research into the biological effects of radiation.

The amount of ionizing radiation required to produce the same biological effect as one rad of high-penetration x-rays.

The SI unit for the amount of ionizing radiation required to produce the same biological effect as one rad of high-penetration x-rays, equivalent to a gray for x-rays.

A unit for measuring absorbed doses of radiation, equivalent to one roentgen of x-rays or gamma rays.

In the International System of Units, the derived unit of radiation dose; the dose received in one hour at a distance of 1 cm from a point source of 1 mg of radium in a 0.5 mm thick platinum enclosure. Symbol: Sv

Initialism of rapid eye movement, a sleep state.

A dose of absorbed radiation equivalent to one roentgen of X-rays or gamma rays.

(computing) A remark; a programming language statement used for documentation (in BASIC for example); also used in DOS batch files.

(web design) A unit relative to the declared font size of the root element in a HTML document.

(knitting) remaining.

A recurring sleep state during which dreaming occurs; a state of Rapid Eye Movements during sleep

(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