Vinculum

·noun A bond of union; a tie.

II. Vinculum ·noun A band or bundle of fibers; a fraenum.

III. Vinculum ·noun A commissure uniting the two main tendons in the foot of certain birds.

IV. Vinculum ·noun 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.