Vinculum

(n.) A bond of union; a tie.

(n.) 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.

(n.) A band or bundle of fibers; a fraenum.

(n.) A commissure uniting the two main tendons in the foot of certain birds.

整理:鲁道夫