surgere

Latin surgere meant 'to rise, to get up' — a compound of sub- (from below) and regere (to direct, to straighten). The original image is of something directing itself upward from underneath. Soldiers surged to their feet. Water surged over riverbanks. The word carried the sense of motion that begins below and pushes up through a surface. It entered Old French as surgir and crossed to English as 'surge' by the late 15th century.

The nautical use came first in English. A surge was a large wave or swell — water rising higher than expected, overwhelming barriers. Elizabethan sailors described the surge of the Atlantic as the dominant experience of ocean travel. Storm surges — the catastrophic rise in sea level caused by hurricanes — were named by the 18th century. The 1900 Galveston hurricane killed 8,000 people, mostly from the storm surge that submerged the island under 4.5 meters of water.

Electrical engineers adopted 'surge' in the 19th century for a sudden, temporary increase in voltage or current. A power surge could destroy equipment, start fires, and kill. The metaphor was exact: electrical force rising suddenly from below, overwhelming the capacity of the circuit to contain it. Surge protectors, surge arrestors, and surge capacity entered the technical vocabulary by the early 20th century.

The word found new life in the 21st century. A 'surge' in troop deployments (the 2007 Iraq surge), a surge in COVID cases, a surge in demand, a surge in popularity. Each use preserves the Latin core: something rising from below, pushing through a surface that was supposed to contain it. Surgere is what happens when the force underneath exceeds the strength of the barrier above.