The Collaborative International Dictionary of English v.0.48:

Ur \Ur\, Ure \Ure\, n. (Zool.)
   The urus.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Urus \U"rus\, n. [L.; of Teutonic origin. See Aurochs.]
   (Zool.)
   A very large, powerful, and savage extinct bovine animal
   (Bos urus or Bos primigenius) anciently abundant in
   Europe. It appears to have still existed in the time of
   Julius Caesar. It had very large horns, and was hardly
   capable of domestication. Called also, ur, ure, and
   tur.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Ur
    n 1: an ancient city of Sumer located on a former channel of the
         Euphrates River

Easton's 1897 Bible Dictionary:

Ur
   light, or the moon city, a city "of the Chaldees," the
   birthplace of Haran (Gen. 11:28,31), the largest city of Shinar
   or northern Chaldea, and the principal commercial centre of the
   country as well as the centre of political power. It stood near
   the mouth of the Euphrates, on its western bank, and is
   represented by the mounds (of bricks cemented by bitumen) of
   el-Mugheir, i.e., "the bitumined," or "the town of bitumen," now
   150 miles from the sea and some 6 miles from the Euphrates, a
   little above the point where it receives the Shat el-Hie, an
   affluent from the Tigris. It was formerly a maritime city, as
   the waters of the Persian Gulf reached thus far inland. Ur was
   the port of Babylonia, whence trade was carried on with the
   dwellers on the gulf, and with the distant countries of India,
   Ethiopia, and Egypt. It was abandoned about B.C. 500, but long
   continued, like Erech, to be a great sacred cemetery city, as is
   evident from the number of tombs found there. (See ABRAHAM.)

     The oldest king of Ur known to us is Ur-Ba'u (servant of the
   goddess Ba'u), as Hommel reads the name, or Ur-Gur, as others
   read it. He lived some twenty-eight hundred years B.C., and took
   part in building the famous temple of the moon-god Sin in Ur
   itself. The illustration here given represents his cuneiform
   inscription, written in the Sumerian language, and stamped upon
   every brick of the temple in Ur. It reads: "Ur-Ba'u, king of Ur,
   who built the temple of the moon-god."

     "Ur was consecrated to the worship of Sin, the Babylonian
   moon-god. It shared this honour, however, with another city, and
   this city was Haran, or Harran. Harran was in Mesopotamia, and
   took its name from the highroad which led through it from the
   east to the west. The name is Babylonian, and bears witness to
   its having been founded by a Babylonian king. The same witness
   is still more decisively borne by the worship paid in it to the
   Babylonian moon-god and by its ancient temple of Sin. Indeed,
   the temple of the moon-god at Harran was perhaps even more
   famous in the Assyrian and Babylonian world than the temple of
   the moon-god at Ur.

     "Between Ur and Harran there must, consequently, have been a
   close connection in early times, the record of which has not yet
   been recovered. It may be that Harran owed its foundation to a
   king of Ur; at any rate the two cities were bound together by
   the worship of the same deity, the closest and most enduring
   bond of union that existed in the ancient world. That Terah
   should have migrated from Ur to Harran, therefore, ceases to be
   extraordinary. If he left Ur at all, it was the most natural
   place to which to go. It was like passing from one court of a
   temple into another.

     "Such a remarkable coincidence between the Biblical narrative
   and the evidence of archaeological research cannot be the result
   of chance. The narrative must be historical; no writer of late
   date, even if he were a Babylonian, could have invented a story
   so exactly in accordance with what we now know to have been the
   truth. For a story of the kind to have been the invention of
   Palestinian tradition is equally impossible. To the unprejudiced
   mind there is no escape from the conclusion that the history of
   the migration of Terah from Ur to Harran is founded on fact"
   (Sayce).


Hitchcock's Bible Names Dictionary (late 1800's):

Ur, fire, light, a valley