Where does the term cat-o’-nine-tails come from and What does cat-o’-nine-tails mean?

In this day it seems amazing that the cat-o’-nine-tails instrument of punishment was actually authorized in the British Navy until as recently as 1881.

It came into use in the late seventeenth century, and was probably greatly modified from time to time according to the nature of the person commanding the punishment and its duration, but at best the bare back of its victim might be literally flayed.

A description in 1788 says it “consists of a handle or stem, made of rope three inches and a half in circumference, and about eighteen inches in length, at one end of which are fastened nine branches, or tails, composed of log line, with three or more knots upon each branch.”