DOCK, a word applied to (1) a plant (see below), (2) an artificial basin for ships (see below), (3) the fleshy solid part of an animal's tail, and (4) the railed-in enclosure in which a prisoner is placed in court at his trial. Dock (1) in O.E. is docce, represented by Ger. Dockea-blatter, O.Fr. docque, Gael. dogha; Skeat compares Gr., a kind of parsnip. Dock (2) appears in Dutch (dok) and English in the 16th century; thence it was adopted into other languages. It has been connected with Med. Lat. doga, cap, Gr., receptacle, from , to receive. Dock (3), especially used of a horse or dog, appears in English in the 14th century; a parallel is found in Icel. docke, stumpy tail, and Ger. Docke, bundle, skein, is also connected with it. This word has given the verb "to dock," to cut short, curtail, especially used of the shortening of an animal's tail by severing one or more of the vertebrae. The English Kennel Club (Rules, 1905, revised 1907) disqualifies from prize-winning dogs whose tails have been docked; several breeds are, however, excepted, e.g. varieties of terriers and spaniels, poodles, etc., and such foreign dogs as may from time to time be determined by the club. The prisoners' dock (4) is apparently to be referred to Flem. dok, pen or hutch. It was probably first used in thieves' slang; according to the New English Dictionary it was known after 1610 in "bail-dock," a room at the corner of the Old Bailey left open at the top, "in which during the trials are put some of the malefactors" (Scots. Mag., 1753).
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)