Why do the words flammable and inflammable have the same meaning?

Question

They both mean the item can catch on fire, why use two words to describe the same thing?

Answer 1

Blame it on Latin and its tricky prefixes. In the beginning, there was "inflammable," a perfectly nice English word based on the Latin "inflammare," meaning "to kindle," from "in" (in) plus "flamma" (flame). "Inflammable" became standard English in the 16th century. So far, so good.

Comes the 19th century, and some well-meaning soul dreamt up the word "flammable," basing it on a slightly different Latin word, "flammare," meaning "to set on fire." There was nothing terribly wrong with "flammable," but it never really caught on. After all, we already had "inflammable," so "flammable" pretty much died out in the 1800's.

"But wait," you say, "I saw 'flammable' just the other day." Indeed you did. "Flammable" came back, one of the few successful instances of social engineering of language.

The Latin prefix "in," while it sometimes means just "in" (as in "inflammable"), more often turns up in English words meaning "not" (as in "invisible" -- "not visible"). After World War Two, safety officials on both sides of the Atlantic decided that folks were too likely to see "inflammable" and decide that the word meant "fireproof," so various agencies set about encouraging the revival of "flammable" as a substitute. The campaign seems to have worked, and "inflammable" has all but disappeared.

That left what to call something that was not likely to burst into flames, but here the process of linguistic renovation was easier. "Non-flammable" is a nice, comforting word, and besides, it's far easier on the tongue than its now thankfully obsolete precursor, "non-inflammable."

Answer 2

Inflammable is the English word, meaning that something is capable of being inflamed or in flames. The opposite is non-inflammable. This all proved too much for our American cousins who came up with the words flammable and non-flammable. In the general dumbing down of the English language, these words have crept into common use.

Answer 3

Usage note: Inflammable and flammable both mean “combustible.” Inflammable is the older by about 200 years. Flammable now has certain technical uses, particularly as a warning on vehicles carrying combustible materials, because of a belief that some might interpret the intensive prefix in- of inflammable as a negative prefix and thus think the word means “noncombustible.” Inflammable is the word more usually used in nontechnical and figurative contexts: The speaker ignited the inflammable emotions of the crowd.

Answer 4

The best I can come up with is flammable means easy to catch on fire and inflammable means able to catch on fire.

Answer 5

Flammable is based on "flame" and inflammable is based on "enflame", which is the short answer. Why somebody decided to make inflammable out of enflame instead of flammable (which would certainly seem more natural, and would have inflammable meaning CAN'T be caught on fire), is the real question, and I don't have an answer, sorry.

Answer 6

The correct word is really "inflammable" but I think they started using "flammable" for safety reasons since people might think "inflammable" means "not able to burn", as in, "it says this gasoline is inflammable, so I'll just light up a cigarette".

Answer 7

You are right they both mean the same thing but there is a BIG difference.... both can catch on fire when lit but only the flammable one can spontaneously catch on fire !!

Answer 8

They both have diffrent meanings. Flammable- the item or contents can ignite easily by spark, flame, or excessive heat.
Inflammable- Unable to be ignited by flame, spark, or excessive heat.

Answer 9

Latin is such a tricky language; so many nuances and extra cases to deal with. It's a classic case of misinterpretation by non-speakers of the original language.

flam·ma·ble (flm-bl) KEY

ADJECTIVE:

Easily ignited and capable of burning rapidly; inflammable.

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ETYMOLOGY:
From Latin flammre, to set fire to, from flamma, flame; see bhel- 1 in Indo-European roots

OTHER FORMS:
flamma·bili·ty (Noun), flamma·ble (Noun)
Usage Note:
Historically, flammable and inflammable mean the same thing. However, the presence of the prefix in- has misled many people into assuming that inflammable means "not flammable" or "noncombustible." The prefix -in in inflammable is not, however, the Latin negative prefix -in, which is related to the English -un and appears in such words as indecent and inglorious. Rather, this -in is an intensive prefix derived from the Latin preposition in. This prefix also appears in the word enflame. But many people are not aware of this derivation, and for clarity's sake it is advisable to use only flammable to give warnings
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in·flam·ma·ble (n-flm-bl) KEY

ADJECTIVE:

1.Easily ignited and capable of burning rapidly; flammable. See Usage Note at flammable.
2.Quickly or easily aroused to strong emotion; excitable.

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ETYMOLOGY:
Middle English, liable to inflammation, from Medieval Latin inflammabilis, from Latin inflammare, to inflame ; see inflame

Answer 10

I guess inflammable comes from "to inflame" as in liable to catch fire...
and flammable just comes from flame, also as in liable to catch fire