Magdeburg hemisphere

noun Physics.

one of a pair of hemispherical cups from which air can be evacuated when they are placed together: used to demonstrate the force of air pressure.

Origin of Magdeburg hemisphere

after Magdeburg, where German statesman and physicist Otto von Guericke (1602–86) constructed a pair of such hemispheres Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019