The meaning of the word 'Tsunami' is

The Japanese word tsunami literally means harbour wave.

Oceanic wave is a general term, not the literal meaning of the word.

Coastal wave does not capture the harbour sense of the term.

Oceanic earthquake names a cause of tsunamis, not the meaning of the word itself.

The name combines tsu for harbour and nami for wave.

Tsunamis are usually triggered by undersea earthquakes displacing large volumes of water.