The Japanese word tsunami is a compound of tsu ("harbour") and nami ("wave"). It is a strikingly accurate name. A tsunami is barely visible in deep water; what makes it dangerous is the way it grows tall and steep when it enters the shallow water of a harbour or coast. Fishermen at sea sometimes did not feel the wave pass beneath them — only to return home and find their villages destroyed.
Replacing "Tidal Wave"
In 19th- and early 20th-century English, the standard term for these events was "tidal wave." The phrase was technically wrong — tsunamis are caused by undersea earthquakes, landslides, or volcanic eruptions, not by tides — but it stuck for the same reason many inaccurate phrases stick: it was vivid. Scientists pushed back. By the 1960s, the more accurate Japanese term had been widely adopted in oceanography and journalism. After the 2004 Indian Ocean tsunami, "tidal wave" largely vanished from English usage altogether.
First English Use
The English word "tsunami" first appears in print in 1897, in an article by the Greek-Irish-Japanese writer Lafcadio Hearn, who was living in Japan and reporting on a major tsunami of 1896. The wave killed more than 22,000 people, and Hearn's essay introduced English readers to the precise Japanese term. For most of the next century, the word remained relatively specialised, used mainly in scientific and travel writing.
A Word About Spelling
The initial "ts" cluster is unusual in English — it does not appear at the start of any native English word. English speakers often pronounce the "t" silently, saying "soo-NAH-mee," but the original Japanese pronunciation includes both consonants, with a soft "ts" rather like the sound at the end of "cats." The retention of the "ts" spelling is a small mark of respect for the source language — a kind of typographic acknowledgement that this is a Japanese word, even when said by a non-Japanese speaker.