Source : Webster's Revised Unabridged Dictionary (1913)

Vinculum \Vin"cu*lum\, n.; pl. L. {Vincula}, E. {Vinculums}.
   [L., from vincire, vinctum, to bind.]
   1. A bond of union; a tie.

   2. (Math.) A straight, horizontal mark placed over two or
      more members of a compound quantity, which are to be
      subjected to the same operation, as in the expression
      x^{2} + y^{2} - vinc{x + y}.

Source : WordNet®

vincula
     See {vinculum}