destroyer n.

late 14c., destruier, destroier, "a plunderer, a killer," agent noun from the verb in English (see destroy) and from Old French destruiere, from destruire.

As a type of small, fast warship, 1894, short for torpedo-boat destroyer (1885); their original purpose was to guard battleships and commercial ships against attacks from small, swift torpedo-boats (a name attested from 1864 in the American Civil War). An important design modification of the torpedo-boat, confusingly, was named "Destroyer," designed by John Ericsson and launched late in 1878 in New York but never brought in service in the U.S. Navy. The has been generally called destroyers since World War I, when their chief purpose shifted to escort work and attacking submarines.