津波
つなみ
tsunami
= tsunami; tidal wave caused by earthquakes
“Tsunami” is one of the clearest examples of a Japanese word that has passed directly into the world’s languages unchanged. Coined from 津 (harbor) and 波 (wave), the term captures a precise natural phenomenon that Japanese coastal communities had long observed and named.
津波 refers to a series of large ocean waves generated by a sudden displacement of water, most often caused by an undersea earthquake. Unlike wind-driven waves, a tsunami carries enormous energy across the full depth of the ocean and becomes dramatically taller as it enters shallow coastal waters — which is why its effects are most severe in ports and harbors rather than in the open sea. In Japanese, the word is used in official weather warnings (津波警報, tsunami keihō), evacuation orders, and everyday disaster-preparedness contexts. In English and most other languages, “tsunami” has fully replaced the older, inaccurate term “tidal wave,” since the phenomenon has nothing to do with tides.
English speakers already know this word, but Japanese learners sometimes mispronounce it. In Japanese, every syllable is evenly weighted: tsu-na-mi (ツ・ナ・ミ), with no stress accent. The “tsu” sound (ツ) does not exist in English natively, so practice it as a single syllable, not “soo” or “tsoo.” Also note that 津波 in Japanese is purely a factual, technical noun used in official contexts such as weather bulletins and evacuation notices — it does not carry dramatic or sensational connotations in everyday Japanese usage.
津波 is written with two kanji. 津 (つ) originally meant a harbor, port, or ferry crossing — a place where water meets land. 波 (なみ) means wave. Together they form 津波: literally “harbor wave.” The pairing reflects a key characteristic of the phenomenon: out in deep water, a tsunami may pass almost unnoticed beneath a ship, but as it approaches the shallower water of a harbor or bay, it slows, compresses, and rises dramatically. Early Japanese coastal observers named it for where the danger became visible, not for where it originated.
Everyday use
津波警報が発令されたので、すぐに高台へ避難してください。
Tsunami keihō ga hatsurei sareta node, sugu ni takadai e hinan shite kudasai.
A tsunami warning has been issued, so please evacuate to higher ground immediately.
Casual / Social Media
今日は地域の津波避難訓練に参加してきました。いざというときのために大切ですね。
Kyō wa chiiki no tsunami hinan kunren ni sanka shite kimashita. Iza to iu toki no tame ni taisetsu desu ne.
I took part in the local tsunami evacuation drill today. It’s important to be prepared when the time comes.
Formal / Cultural context
「津波」という語は現在、国際的な科学用語として世界中で使われています。
“Tsunami” to iu go wa genzai, kokusaiteki na kagaku yōgo toshite sekaijū de tsukawarete imasu.
The word “tsunami” is now used worldwide as an international scientific term.
The word “tsunami” entered international scientific usage gradually throughout the twentieth century and became universally recognized after major seismic events in the Pacific and Indian Oceans prompted global cooperation on early-warning systems. Before this standardization, English-speaking media used the term “tidal wave,” which geologists considered misleading because the phenomenon is unrelated to tidal forces. The adoption of the Japanese term reflects both the precision of the original word and Japan’s long history of documenting and responding to this type of event along its coastline.
In Japan, tsunami preparedness is deeply embedded in public life. Coastal municipalities maintain hazard maps (ハザードマップ, hazādo mappu) that mark evacuation routes and designated high-ground assembly points. Annual drills are held in schools and communities, and tsunami warning signs are posted along coastal roads. This culture of preparedness has developed over centuries of living in a seismically active region, and the vocabulary surrounding 津波 — including 津波警報 (warning), 津波注意報 (advisory), and 高台避難 (evacuation to high ground) — reflects how thoroughly the concept is integrated into everyday safety awareness.