Improvised vehicle armour
Improvised vehicle armour is a form of vehicle armour consisting of protective materials added to a vehicle such as a car, truck, or tank in an irregular and extemporized fashion using available materials. Typically, improvised armour is added in the field and it was not originally part of the design, an official up-armour kit, nor centrally planned and distributed.
Source: Wikipedia — Improvised vehicle armour (CC BY-SA 4.0)