Flammable vs. Inflammable
Both words mean the same thing, but one of them is bound to confuse most people.
What to KnowFlammable and inflammable look like opposites, but they both describe something that ignites easily and burns quickly. While the prefix in- is most familiar in its “not” meaning, as in inactive and inaccurate, the in- in inflammable is another prefix altogether: it means “to cause to be,” as in the words indent and indebted. Using flammable for what burns and nonflammable for what does not burn is an option if you want to ensure clarity.
"When cooking over a gas stove, avoid wearing loose, (flammable/inflammable) clothing that could catch fire easily." Which word is correct: flammable or inflammable?
It's a trick question. Both flammable and inflammable are correct, as they both mean "capable of being easily ignited and of burning quickly." This makes no sense to the Modern English speaker. In English, we think of in- as a prefix that means "not": inactive means "not active," inconclusive means "not conclusive," inconsiderate means "not considerate." Therefore, inflammable should mean "not flammable."
What's the difference between 'flammable' and 'inflammable'?
The Latin Inflammare
That would make sense if inflammable had started out as an English word, but it didn't. We get inflammable from the Latin verb inflammare, which combines flammare ("to catch fire") with a Latin prefix in- (more commonly seen as en- in English, as in enfold) meaning "to cause to be." This in- shows up occasionally in English words, such as indent and indebted, and it showed up in inflammable in the early 1600s.
All was fine with this situation until 1813, when a scholar translating a Latin text coined the English word flammable from the Latin flammare. Now we had a problem: two words that look like antonyms but are actually synonyms. There has been confusion between the two words ever since.
The True Opposite of Inflammable
What do you do? If you want to keep things crystal clear, choose flammable when you are referring to something that catches fire and burns easily, and use the relatively recent nonflammable when referring to something that doesn't catch fire and burn easily. Inflammable is just likely to enflame confusion.
