A combination order whereby two separate orders are entered on the same security. The execution of one order cancels the other.
For example, if you purchased shares of XYZ at $5, you could enter an alternative order to sell at either $2.50 or $7.50. If the order to sell at $2.50 was executed, the $7.50 order would be cancelled and vice versa. This would limit potential losses and gains, thus mimicking a collar strategy.