The symbol representing long division does not actually have a name. It is usually simply referred to as a "long division symbol" or a "division bracket."
A long division symbol looks like a right or closing parenthesis ")" attached to a long vertical bar. The right parenthesis is sometimes replaced by a small horizontal bar.
The long division symbol has been around since at least the 1880s. To use this symbol, the dividend is located to the left of the ")" and the quotient is typically written under the line. The answer to the problem is written above the quotient, on top of the horizontal line.