The use of ‘tidal wave’ for a large, destructive ocean wave, most usually produced by a submarine earthquake, volcanic eruption, or coastal landslide, but also possibly by a hurricane, or strong wind, is a misnomer – for it has no connection with the tides. The phrase ‘tidal wave,’ which first appeared in 1830, is actually either of the two great wavelike swellings of the ocean surface that move around the earth on opposite sides and give rise to tides, caused by the attraction of the moon and sun. Sometime in the 1800s (see 1878 quote), ‘tidal wave’ became confused with what now might properly be called a ‘seismic sea wave’ or ‘tsunami’ (Japanese, from ‘tsu,’ port, harbor + ‘nami’ wave, first appearing in English print in 1897). The original misuse of ‘tidal wave’ was probably a result of the fact that there was no proper generally recognized word for the phenomenon at the time and it, more or less, filled the void. ‘Tidal wave’ was being used figuratively as a great progressive movement or manifestation of feeling, opinion, or the like by 1870 (see quote below). ‘Tsunami’ wasn’t being used in a similar figurative sense until about 1970.
Today, many dictionaries still list ‘tidal wave’ as a synonym for ‘tsunami,’ although it is being used less and less and, in fact, I did not see that word used once in reference to Sunday’s disaster.
(Oxford English Dictionary, Random House and Merriam-Webster’s Unabridged Dictionaries)<1830 “On mathematical principles, the rise of the TIDAL WAVE above the mean level of a particular sea must be greater than the fall below it.”—‘Principles of Geology’ by Lyell, I. page 293>
<1870 “We'll have somebody standing ready to launch a book right on our big TIDAL WAVE and swim it into a success.”—‘Letters to Publishers’ (1967) by Mark Twain, page 45> [[early figurative use]]
<1878 “The terrible devastation wrought by the great TIDAL WAVE, which followed the earthquake at Lima”—‘Physiography: An introduction to the Study of Nature’ by T. S. Huxley, page 2>
<1888 “Now and then . . . there comes a rush of feeling so sudden and tremendous, that the name of TIDAL WAVE has been invented to describe it.”—‘The American Commonwealth,’ by Bryce, III. iv. lxxx. page 62>
<1897. 24 ‘TSUNAMI!’ shrieked the people; and then all shrieks and all sounds and all power to hear sounds were annihilated by a nameless shock . . . as the colossal swell smote the shore with a weight that sent a shudder through the hills.”—‘Gleaning in Buddha-Fields’ by L. Hearn, i. page 24>
<1899 “The TIDAL WAVE sweeps round the earth twice in the twenty-four hours; the great wave produced by an earthquake, erroneously described sometimes as a ‘TIDAL WAVE’, has nothing tidal about it, and it is called by scientific men ‘a free wave’.”—‘Daily News,’ 13 June, page 8/2>
<1972 “The Food and Drug Administration . . . is currently swimming through a TSUNAMI of comments generated by its announced intention to alter the regulations concerning the dispensation of methadone.”—‘Science,’ 11 August, page 502/1>
Submitted by Ken Greenwald (Fort Collins, CO - U.S.A.)