Esquire (1)
Ranking immediately below a knight, an esquire was a knight's companion and armour bearer.
In times when every title implied some particular and well-known charge or office, and, consequently, the distinction of ranks was more easily and more carefully observed, it would have been less difficult to define the title of esquire than it is in the present day. The epithet noble has long been appropriated to peers of the realm, but it was originally synonymous with gentle, and belonged to all such as were entitled to coat-armour. Of these the esquires formed the lowest degree except one, occupying a rank between knights and gentlemen. It is manifest that the word is derived from the Old French escuyer, but the origin of this is variously stated.
Pasquier traces it up to the later times of the Roman empire, when there were two kinds of soldiery in its armies, the Gentiles and the Scutarii, the latter of whom, he maintains, have perpetuated their name with very little alteration. That different bodies of troops in the Roman armies were thus distinguished is very probable, but that one of them was the predecessor of the esquires of the middle ages is an hypothesis which we will leave, as in its proper place, among the “Recherches” of that learned antiquarian. But, although I think we may safely reject this etymology, it is not very easy to substitute another which carries more probability with it: if we suppose with some that the earliest esquires were no other than attendants who had the care of the stables and horses, the Latin word equus may have been the common origin of equerry and esquire. Or, without going so far back as the Scutarii of Pasquier, we may trace the word escuyer to scutum, through scutifer, or shield-bearer; for we know that to bear the shield and other arms of a knight was part of the duty of an esquire, and the earliest duty, too, which we know certainly to have belonged to him. This office is expressed by armiger, the present established Latin appellation for esquire.
But, however this may be with respect to the name, the character formed no inconsiderable figure in the times of chivalry. Whether in history or romance, (and, at that period, they are strangely blended) we should as soon expect to meet with a knight without his lance or helmet as without one esquire at least: he was lawfully entitled to two, and this privilege is still retained on the only occasion on which it can exercised: at all installations of Knights of the Bath, each knight is attended by two esquires. This is a ceremony confined solely to the Order of the Bath. At coronations, also, each Knight of the Bath is attended by his two esquires.
As the office of an esquire as a knight’s attendant grew less frequent, the name grew more into use, as a title to men of a different kind, and seems to have been laid hold of as a readymade, and then almost unoccupied, term, which would very well have served as a distinction for the younger Sons of noblemen, who had no other title, and for such as held any office of importance in the country. Besides the younger sons of peers, who are now called honourable, the rank of esquire belonged to their eldest sons, to the eldest Sons of knights and their eldest sons, to sheriffs of counties, serjeants at law, justices of the peace and doctors of divinity; these last were excluded from the use of the title by the appellation of reverend which precedes their name.
The sovereign sometimes used to create an esquire by putting round his neck a silver collar of SS, to which ceremony was formerly added the putting on of a pair of silver spurs. The king could also create an esquire by patent. The heads of ancient families were considered esquires by prescription. [from W. Berry]
The term is now widely used indiscriminately as a courtesy title and added to the end of the name of any male when addressing an envelope, replacing Mr which precedes the name .
Esquire (2), Esquirre, Equire, Squire
1. A rare and ancient terms for the gyron.

2. An obscure ancient term descriptive of a pile when formed by a horizontal line on one side and an angled line on the other. The illustration is that of a baste esquire.