BAY, a homonymous term of which the principal branches are as follows, (1) The name of the sweet laurel (Laurus nobilis) or bay tree (see Laurel); this word is derived through the O. Fr. baie, from Lat. baca, berry, the bay bearing a heavy crop of dark purple berries. The leaves of the bay were woven in garlands to crown poets, and hence the word is often used figuratively in the sense of fame and reward. (2) A wide opening or indentation in a coast line. This may be of the same origin as "bay," in the architectural sense, or from a Latin word which is seen in the place name Baiae. (3) The name of a colour, of a reddish brown, principally used of the colour in horses; there are various shades, light bay, bright bay, etc. This word is derived from the Latin badius, which is given by Varro (in Nonnius, pp. 80-82) as one of the colours of horses. The word is also seen in baize (q.v.). (4) The deep bark of dogs. This word is also seen in the expression "at bay," properly of a hunted animal who at the last turns on the "baying" hounds and defends itself. The origin of the word is the O. Fr. bayer, abayer, Lat. badare, properly to gape, open wide the mouth. (5) An architectural term (Fr. travée, Ital. compartimento, Ger. Abteilung) for any division or compartment of an arcade, roof, etc. Each space from pillar to pillar in a cathedral, church or other building is called a "bay" or "severy." This word is also to be referred to bayer, to gape.
A "bay-window" or "bow-window" is a window projecting outwards and forming a recess in the apartment. Bay-windows may be rectangular, polygonal or semicircular in plan, in the last case being better known as bow-windows. The bay-window would seem to have been introduced in the 15th century, but the earliest examples of importance are those which were built during the reign of Edward IV. (1461-1483), when it was largely employed in the colleges of Oxford and Cambridge and in the feudal castles of the period. Examples are found in the palace at Eltham, Cowdray Castle in Sussex, Thornbury Castle in Gloucestershire, and in the George Inn at Glastonbury; one of the finest of a later date is that of the Banqueting Hall at Hampton Court, some 50 ft. high. In the great entrance halls of ancient mansions the floor of the last bay of the hall was generally raised two or three steps, and this portion was reserved for the lord of the manor and his guests, and was known as the dais. The usual position of the bay-window is at one end of this dais, and occasionally but rarely at both ends. The sills of the windows are at a lower level than those in the hall, and, raised on one or two steps, are seats in the recess. The recess of the bay-window was generally covered with a ribbed vault of elaborate design, and the window itself subdivided by mullions and transoms. In some of the larger windows such as those at Cowdray and Hampton Court there are no fewer than five transoms, and this sub-division gave great scale to the design. The same feature when employed in an upper storey and supported by corbels or brackets is known as an oriel window. (See also Dais and Hall.)
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)