It is the allowance paid to an employee who is working on a special assignment. This amount is completely exclusive of his Compensation plan. These are given in scenerio's like, when the employee went for On Job Training or an Employee sent for short term Deputation to survive his expenses in the new location.
There is no specific abbreviation for the term WIRE because when the payment is being made using this option, you will not see the physical movement of funds. It is all electronic. It is just like a current passes through Wire.
Therefore Electronic movement of funds is campared with WIRE.