Etymology Usage

Flame proof

Q: I disagree that “flammable” and “inflammable” mean the same thing. “Flammable” means consisting of materials that will burn if lit. “Inflammable” means can be lit. Example: “In normal humidity, the grasses of Secaucus, NJ, are flammable, but not inflammable. When it’s dry, they’re inflammable.” I always try to maintain distinctions.

A: We believe in maintaining distinctions too—where distinctions exist. But “inflammable” and “flammable” have identical meanings. We can’t find any dictionary definitions that would support your case.

We’ve written about this on our blog, but that was a while ago. We wrote about it more recently in our book Origins of the Specious.

In Origins, we note that some people insist “inflammable” means not burnable, but is misused to mean burnable. Others say it does indeed mean burnable, but it’s merely a puffed-up, redundant version of “flammable.” Here’s an excerpt from the book:

“For the record, ‘inflammable’ does mean ‘burnable.’ And it’s meant that since at least 1605, according to the Oxford English Dictionary. ‘Flammable,’ the new kid on the block, didn’t appear in print until more than three hundred years later.

“The cause of all the confusion is the ‘in’ at the beginning of ‘inflammable.’ It turns out that the prefix in– can make a word negative (as in words like ‘incapable,’ ‘inflexible,’ ‘incompetent’), or it can add emphasis (‘invaluable,’ ‘inflame,’ ‘intense’), or it can mean ‘within’ (‘incoming,’ ‘inbreeding,’ ‘infighting’). The in– of ‘inflammable’ is of the emphatic type—it’s called an intensive or an intensifier. The word ‘inflammable’ comes from the Latin inflammare, meaning to inflame. The upstart ‘flammable’ was coined in the early nineteenth century, but for decades it was rarely used. So how did ‘flammable’ eventually catch fire?

“We can thank the National Fire Protection Association for this one. In the 1920s it called for using ‘flammable’ instead of ‘inflammable,’ which it considered confusing because of that in- at the beginning. Insurers and other fire-safety advocates soon joined the cause. In 1959, the British Standards Institution took up the torch: ‘In order to avoid any possible ambiguity, it is the Institution’s policy to encourage the use of the terms ‘flammable’ and ‘non-flammable’ rather than ‘inflammable’ and ‘noninflammable.’ ”

“Which word should a careful writer use today? Well, history may be on the side of ‘inflammable,’ but common sense wins here. If you want to be sure you’re understood—say, the next time you see a smoker about to light up near a gas pump—go with ‘flammable.’ ”

We’ll grant you this—if “flammable” had been the original word, and if the prefix had been ADDED as in intensifier (yielding a word that meant extra flammable), then the distinction you talk about might make sense.

Unfortunately, the history of the development of these words doesn’t bear out such an interpretation.

Check out our books about the English language