from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A whip consisting of nine knotted cords fastened to a handle, used in flogging.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A similarly constructed leather nine-tail whip, as used in British penal colonies and certain armies
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a whip with nine knotted cords
So called because it leaves marks like the scratches of a cat.(American Heritage® Dictionary of the English Language, Fourth Edition)
From cat + of + nine + tail, attested 1695. (Wiktionary)