Tsunami is a Japanese word that is made of two
characters: tsu and nami. The character tsu means
harbor, while the character nami means wave.
Therefore, the original word tsunami describes large
wave oscillations inside a harbor during a ‘tsunami’
event. In the past, tsunami is often referred to as
‘tidal wave’, which is a misnomer. Tides, featuring
the rising and falling of water level in the ocean in a
daily, monthly, and yearly cycle, are caused by
gravitational influences of the moon, sun, and planets.
Tsunamis are not generated by this kind of
gravitational forces and are unrelated to the tides,
although the tidal level does influence a tsunami
striking a coastal area.