Pronunciation: ' rik-t ə r-
Function: noun
Etymology: Charles F. Richter
Date: 1938
: an open-ended logarithmic scale for expressing the magnitude of a seismic disturbance (as an earthquake) in terms of the energy dissipated in it with 1.5 indicating the smallest earthquake that can be felt, 4.5 an earthquake causing slight damage, and 8.5 a very devastating earthquake