vinculum (VING-kyuh-lum) noun
1. A bond or tie. (Vinculum matrimonii is Latin for the bond of marriage).
2. Mathematics: A horizontal bar placed over two or more terms to show that they are to be treated together, equivalent to enclosing them in a parenthesis.
3. Anatomy: A ligament.
From Latin vinculum (fetter), from vincire (to tie).