Dear Geist,
Why do we have two words, almost identical, that mean “easily set on fire”? I’m talking about flammable and inflammable. Even dictionary writers seem embarrassed about this weird situation.
—Cathy Glazdar, St. John, NB
Dear Cathy,
The trouble is the in- prefix, which is added to some words to make them mean “not”: sensitive/insensitive, capable/incapable and so on. English borrowed this in- from Latin; but it also borrowed another Latin in- that fortifies some words rather than negating them, such as indoctrinate and inflammable. Somewhere around the turn of the twentieth century, American insurance companies got worried enough about the confusion between flammable and inflammable—on tags attached to baby blankets, for instance—that they pressed manufacturers to use only flammable, whose meaning was unambiguous. Other English-speaking countries have followed suit, but both terms are still in wide use. We recommend flammable, or the more recent non-flammable. Why play with fire, eh?
—The Editors