A friend of mine works in a retail store of a large company. A couple of weeks ago, the employees were asked to stay late one evening for a training session on safety. Most companies worldwide these days are emphasizing the importance of security, and this company wants to make sure all of its employees know the basics of good security.
During the workshop, one of the employees raised the question of what was the difference between "flammable" and "inflammable." The person conducting the seminar had not been asked this question before and did not know specifically the difference between the two, although he was quite sure both words meant the same thing: capable of being easily set on fire and of burning quickly.
But that raised some other questions. For example, "inactive" means not active; "inadmissible" means not admissible; "incapable" means not capable; "inseparable" means not separable; and on and on the examples could go. It doesn't make sense that "inflammable" means flammable -- it should mean not flammable, like all the above examples.
The person leading the training session was unable to explain why this was the case, but he was absolutely correct in saying that inflammable and flammable mean the same thing.
Inflammable is by far the older of the two words. The use of inflammable as an English word can be traced as far back as 1605. It is the English translation of the Latin word inflammare, which is the combination of two Latin words: in, which in this case has the same meaning as our English "in," and flamma, which means "flames," hence, "in flames."
Flammable, on the other hand, can be traced only as far back as 1813, meaning that the English word inflammable is at least 208 years older than the English flammable. Flammable, however, can also be traced to the same Latin flamma, "flames." So it is understandable that both words have the same meaning in English.
But that still doesn't explain why inflammable means flammable instead of not flammable. In answering this, we need to keep in mind that it is not always easy to translate one language accurately into another. Sometimes there are not adequate words in the new language to express the exact meaning of the original word, and that is the case with translating old Latin words into modern English. And many times the context in which the original word is used determines the way it should be translated.
The Latin word in can be used in its native language to mean different things, depending on the Latin word it is combined with. For example, when combining in with flamma, the Latin inflammare means capable of being easily ignited -- that is, flammable. But when the Latin in is used with admissus (admissible), it means opposed to being admitted -- that is, not admissible. We have to go back to the original Latin to know how "in" is being used and, therefore, whether it should be translate into English as "in" or "not."
When one thinks of the meaning of the two words, "inflammable" seems more logical than "flammable" because of the combination of "in" and "flames," that is, "in flames." Furthermore, as noted above, inflammable is the older of the two English words by two centuries. It seems strange, therefore, that the older European countries like Italy, France, and England would have favored using the younger term, flammable, but they did. On the other hand, the United States, a relatively young country, favored using the older term, inflammable. We have no explanation for this being the case. One can only hazard a guess: that, by using the older word closer to the original Latin, the leaders of the United States were letting their European counterparts know that they, the leaders in the new country, were intellectually equal or superior to their counterparts in the older European countries. But, this is only a guess. Whatever the reason may have been, that is the way things were until World War II.
During World War II, Allied leaders throughout Europe urged the American companies manufacturing munitions to use only "flammable" when labelling the explosives being sent to Europe. They were afraid that using inflammable might be wrongly interpreted as not flammable, which could result in deadly accidents.
Compliance with this European request was rejected initially by many American companies. The feeling in the United States was that the Americans were doing the Europeans a favor by getting involved in what appeared to many people to be primarily a European war, and they, the Europeans, could, therefore, adjust to the way the American did things. But armed services personnel in the United States were successful in persuading American companies to use flammable by pointing out that not doing so could result in accidents that could harm and kill their own soldiers who were serving side by side their Allies throughout Europe. All armaments sent to Europe by the United States gradually became labelled FLAMMABLE.
Following the War, however, the majority of American companies went back to using inflammable. But, about twenty years after the War, companies in the United States began, again, using flammable instead of inflammable. Finally, in the late 1970s, flammable overtook the use of inflammable in the United States, and now one seldom sees the use of inflammable on either side of the Atlantic or Pacific.
As Paul Harvey, the well-known news broadcaster on ABC for many years, used to say, "And now you know the rest of the story."