This can mean endothermic materials, and is defined as such in other documents. The term ablative has also been used to describe silicone products, which, by themselves, are sacrificial. In other words, given sufficient time under fire or heat conditions, these products actually char away, crumble and disappear. The idea is to put enough of the stuff in the way of the fire, so that a prescribed fire-resistance rating can be maintained. Usually, ablative materials have a large concentration of organic matter, which is reduced by fire to ashes. In the case of silicone, organic rubber surrounds very finely divided silica dust (up to 300m² of combined surface area of all the dust particles per gram of this dust). When the fire comes, it reduces the organic rubber to ash and leaves the silica dust that the product started with. If you burn some silicone caulking and then subsequently crush the remaining ashes, you will find that the interior of the black piece of as is actually white. The silica was white to begin with. The black stuff is the carbonaceous remains of the organic rubber that surrounded each silica dust particle