BORE, a high tidal wave rushing up a narrow estuary or tidal river. The bore of the Severn is produced by a tide that rises 18 ft. in an hour and a half. This body of water becomes compressed in the narrowing funnel-shaped estuary, and heaped up into an advancing wave extending from bank to bank. The phenomenon is also particularly well illustrated in the Bay of Fundy. The origin of this word is doubtful, but it is usually referred to a Scandinavian word bāra, a wave, billow. The other name by which the phenomenon is known, “eagre,” is also of unknown origin. There is, of course, no connexion with “bore,” to make a hole by piercing or drilling, which is a common Teutonic word, cf. Ger. bohren, the Indo-European root being seen in Lat. forare, to pierce, Gr. άροτρο, plough. For the making of deep holes for shafts, wells, &c., see Boring. The substantival use of this word is generally confined to the circular cavity of objects of tubular shape, particularly of a gun, hence the internal diameter of a gun, its “calibre” (see Gun). A “bore” is also a tiresome, wearying person, particularly one who persistently harps on one subject, in or out of season, whatever interest his audience may take in it. This has generally been taken to be merely a metaphorical use of “bore,” to pierce. The earliest sense, however, in which it is found in English (1766, in certain letters printed in Jesse’s Life of George Selwyn) is that of ennui, and a French origin is suggested. The New English Dictionary conjectures a possible source in Fr. bourrer, to stuff, satiate.