What does "seiche" mean?

A short-term standing wave oscillation of the water level in a lake, or other confined body of water such as a fjord, characteristic of its geometry.

Seiche

//seɪʃ// noun

noun ·Rare ·Advanced level

Noun

1
A short-term standing wave oscillation of the water level in a lake, or other confined body of water such as a fjord, characteristic of its geometry.
"In September 2023, we detected the start of a 9-day-long, global . . . very-long-period seismic signal, originating from East Greenland. . . .this event started with a glacial thinning-induced rock-ice avalanche of 25 million cubic meters plunging into Dickson Fjord, triggering a 200-meter-high tsunami. Simulations show that the tsunami stabilized into a 7-meter-high long-duration seiche with a frequency. . .and slow amplitude decay that were nearly identical to the seismic signal. An oscillating, fjord-transverse single force . . . reproduced the seismic amplitudes and their radiation pattern relative to the fjord, demonstrating how a seiche directly caused the 9-day-long seismic signal."
2
a wave on the surface of a lake or landlocked bay; caused by atmospheric or seismic disturbances wordnet

"Wind and weather conditions on the Great Lakes may create a seiche, an oscillating wave which can be several feet high."

From Swiss French seiche, perhaps from German Seiche (“sinking”).

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.