In the past, the scientific community referred to tsunamis as "seismic sea waves". "Seismic" implies an earthquake-related mechanism of generation. Although tsunamis are usually generated by earthquakes, tsunamis are less commonly caused by landslides, infrequently by volcanic eruptions, and very rarely by a large meteorite impact in the ocean.

In the past, tsunamis were often referred to as "tidal waves" by many English speaking people. The term "tidal wave" is a misnomer. Tides are the result of gravitational influences of the moon, sun, and planets. Tsunamis are not caused by the tides and are unrelated to the tides; although a tsunami striking a coastal area is influenced by the tide level at the time of impact. "