The Collaborative International Dictionary of English v.0.48:

Leash \Leash\ (l[=e]sh), n. [OE. lese, lees, leece, OF. lesse,
   F. laisse, LL. laxa, fr. L. laxus loose. See Lax.]
   1. A thong of leather, or a long cord, by which a person may
      hold or restrain an animal, such as a falconer holding his
      hawk, or a courser his dog. For dogs and cats, the leash
      is commonly attached to a collar around the neck of the
      animal.
      [1913 Webster]

            Even like a fawning greyhound in the leash. --Shak.
      [1913 Webster]

   2. (Sporting) A brace and a half; a tierce; three; three
      creatures of any kind, especially greyhounds, foxes,
      bucks, and hares; hence, the number three in general.
      [1913 Webster]

            [I] kept my chamber a leash of days.  --B. Jonson.
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            Then were I wealthier than a leash of kings.
                                                  --Tennyson.
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   3. (Weaving) A string with a loop at the end for lifting warp
      threads, in a loom.
      [1913 Webster]

   To keep (a person) on a short leash to maintain close
      control over the activities of (a person).
      [PJC]