Vinculum
Vinculum , noun
[Latin, from vincire, vinctum, to bind.]
1.
A bond of union; a tie.
2.
(Mathematics) 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 x2 + y2 - x + y.
3.
(Anatomy) A band or bundle of fibers; a fraenum.
4.
(Zoology) A commissure uniting the two main tendons in the foot of certain birds.