A flag may be defined as a piece of pliable material, attached at one end so as to move freely in the wind, serving as a sign or a decoration. This word is now common to the nations of north-western Europe[1], but it does not appear to have come into use in this particular meaning until the sixteenth century, and the etymology of it is obscure. Perhaps the most satisfactory of the derivations hitherto put forward is that of Professor Skeat, who derives it from the Middle English "flakken" to fly, one of a number of similar onomatopoeic words suggestive of the sound of something flapping in the wind. Its first appearance with a meaning coming within the above definition is as a specific term denoting a rectangular piece of material attached by one vertical edge, flown at the masthead of a ship, as a symbol of nationality or leadership. It was not until towards the end of the seventeenth century that the word began to take on the more general meaning it now has, and indeed the restricted meaning still partially survives in the German language, in which the word "Flagge" is properly applicable only to flags flown at sea, those on land being called "Fahnen." Before the seventeenth century there was no generic term in the English language that covered the various forms--banners, ensigns, streamers, pendants, etc.--that are now generally included under the term "flag." A somewhat similar change in meaning has, during the course of centuries, affected nearly every flag name, and constitutes one of the great difficulties in the way of a clear exposition of the early history of flags. Moreover, the early writers are neither consistent in their use of terms nor accurate in their application. This renders the correct interpretation of many passages a matter requiring caution and discrimination and, it may be added, experience. As a guide to the reader we shall set down the principal terms to be met with, and indicate the extent to which their meaning has changed, but before doing so it is desirable to explain one or two technical or semi-technical terms employed in connection with the parts of a flag. The part next the staff or line to which it is attached is called the "hoist" by seamen, or heraldically the head or "chief"; the remainder of the flag is the "fly." The fly may be forked or swallow-tailed. If the end of the fly is divided by a simple incision which does not remove material, it is said to be "slit." The fly may be produced into a number of pointed or round-ended tails, to which the Crusaders gave the name of tongues (_linguae_, _lingulae_). The British and many other ensigns have in the upper part next the staff a rectangular compartment containing a national device. In modern flags this usually occupies one-fourth of the flag, but in early flags it was much smaller. This is called a "canton." The other terms that need explanation at this stage are as follows: