English vocabulary has many words that are commonly confused, like flout and flaunt, jive and jibe, and refute and reject (though with this last pair, things are less clear-cut than some people suppose). Another pair that are often mixed up, sometimes even in edited writing, are defuse and diffuse. If you’re unsure of the distinction, or if you want a mnemonic to remember which is which, read on.
Defuse is a surprisingly modern verb. It emerged during World War II in reference to removing the fuse from a bomb, literally de-fuse, with the prefix de- carrying the sense ‘remove’, as in de-ice and dethrone. Within a few years it was being used figuratively, where instead of an explosive device it was a situation being defused. The fuse had become metaphorical.
This figurative defuse often appears in the context of conflict, or potential conflict, near abstract nouns like situation, tension, criticism, issue, and controversy. Defined in Macmillan Dictionary as ‘to make a situation more relaxed by making people feel less angry or less worried’, it’s now more common than the original, bomb-related sense. But the conceptual link remains.
Diffuse is a much older verb, dating to the 15th century. Like defuse it has both physical and figurative senses. It centres on the idea of something spreading or being distributed: a splash of milk diffuses through a mug of tea; an idea diffuses through a community.
Both verbs have corresponding nouns. Diffusion has various senses to do with the spreading or distribution of something, including technical senses in physics and anthropology, while the rare noun defusion mainly has a specialised meaning in psychiatric texts.
Diffuse, unlike defuse, is also commonly used as an adjective, generally to mean ‘existing over a large area or in many areas’. So a pain that diffuses throughout your body can be called diffuse. Another meaning of the adjective is ‘using too many words and not easy to understand’. An argument could be defused because a speaker is diffuse.
Etymology can help you keep these words separate. See the fuse in defuse and recall the verb’s original meaning. From the idea of removing the danger of a bomb, it’s a short step to reducing conflict in a potentially explosive situation. Alternatively, match the –iff in diffuse with the –iff in whiff and think of a smell diffusing through a room. Hopefully this will help you defuse any trouble you had with the diffuse meanings of these words.Email this Post