Tsunami is a Japanese word with the English translation, "harbor wave." Represented by two characters, the top character, "tsu," means harbor, while the bottom character, "nami," means "wave."
In the past, tsunamis were sometimes referred to as "tidal waves" by the general public and as 'seismic sea waves' by the scientific community.
The term "tidal wave" is a misnomer; although a tsunami's impact upon a coastline is dependent upon the tidal level at the time a tsunami strikes, tsunamis are unrelated to the tides.
Tides result from the imbalanced, extraterrestrial, gravitational influences of the moon, sun, and planets. The term "seismic sea wave" is also misleading. "Seismic" implies an earthquake-related generation mechanism, but a tsunami can also be caused by a non-seismic event, such as a landslide or meteorite impact.
A tsunami is a very long-wavelength wave of water that is generated by sudden displacement of the seafloor or disruption of any body of standing water.
Tsunamis are sometimes called "seismic sea waves", although, as we will see, they can be generated by other mechanisms than earthquakes.
Tsunamis have also been called "tidal waves", but this term should not be used because they are not in any way related to the tides of the Earth. Because tsunamis occur suddenly, often without warning, they are extremely dangerous to coastal communities.