Improvised explosive device and Petrol bomb

Improvised explosive device noun - An explosive device that is improvised.

Petrol bomb and improvised explosive device are semantically related. In some cases you can replace phrase "Petrol bomb" with "Improvised explosive device", this phrases are similar.

Petrol bomb noun - A crude incendiary bomb made of a bottle filled with flammable liquid and fitted with a rag wick.

Improvised explosive device and petrol bomb are semantically related. You can use "Improvised explosive device" instead a noun phrase "Petrol bomb".