noun a bond of union; a tie.
2. vinculum ·noun a band or bundle of fibers; a fraenum.
3. vinculum ·noun a commissure uniting the two main tendons in the foot of certain birds.
4. 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.