a unit of radiation equal to one thousandth of a roentgen
Abbreviation: mR, mr
Word origin
[1950–55; milli- + roentgen]This word is first recorded in the period 1950–55. Other words that entered Englishat around the same time include: International Gothic, action painting, allograph, hot line, point spreadmilli- is a combining form meaning “thousand” (millipede): in the metric system, used in the names of units equal to one thousandth of thegiven base unit (millimeter). Other words that use the affix milli- include: milliequivalent, millifarad, millilambert, millilux, millimicron