Meaning of vinculum

vin•cu•lum

Pronunciation: (ving'kyu-lum), [key]
— pl. -la
  1. a bond signifying union or unity; tie.
  2. a stroke or brace drawn over a quantity consisting of several members or terms, as &aspplusspbhorbarover;, in order to show that they are to be considered together.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.