'fire-retardant' originates from Modern English, specifically the compound of the words 'fire' and 'retardant', where 'fire' referred to combustion or flame and 'retardant' meant 'something that delays'.

'retardant' comes from French 'retarder' (to delay) ultimately from Latin 'retardare' ('re-' back + 'tardare' to make slow). 'Fire' comes from Old English 'fyr' meaning 'fire, flame'; the compound 'fire-retardant' developed in the 20th century with the growth of industrial fire-safety materials.

Initially the components meant 'flame' and 'a thing that delays'; together the compound came to mean materials or treatments that slow burning or reduce flammability.