This Spanish loanword is a synonym for “earthquake.” It comes from the Spanish verb “temblar,” meaning “to tremble,” which came from the Medieval Latin verb “tremulare,” with the same meaning. “Temblor” came into use in the late 19th century, around the same time as some notable earthquakes: In 1872, one of the largest earthquakes in California history struck Owens Valley; in 1883, the Krakatoa volcano erupted in Indonesia, bringing many temblors with the seismic activity; and in 1886, one of the largest earthquakes on the East Coast of the United States struck Charleston, South Carolina.