For most English speakers, the term “an old flame” is so familiar that its meaning is seldom questioned. When the individual words that make up this term are examined, however, it quickly becomes clear that it is an idiom, or an expression with a meaning that cannot be deduced by studying its constituent parts. While it may not be obvious to non-native English speakers, an old flame is a former love interest. The origins of this expression are not clear.
“An old flame” is an idiom, or an expression which cannot be understood by studying the literal meaning of the words which comprise it. Other examples of common English-language idioms include “bent out of shape,” “under the weather,” and “kick the bucket.” Individuals learning a foreign language often find interpreting idioms to be a greater challenge than mastering grammatical rules or learning verb conjugations. This is because the words which constitute an idiom are not to be taken literally, and therefore even a perfect translation of an idiom’s individual words does not shed light on their combined meaning. Sometimes, however, the meaning of an idiom can be deduced by considering the context in which it is used.
English speakers use the term “an old flame” to refer to a former love interest. The use of the word “flame” within the expression refers not, of course, to a literal flame, but rather to the figurative “heat” or passion with which one once regarded his former love interest. Similarly, “old,” within this idiom, refers not to age, but rather to the fact that the relationship between the “flame” and the individual who once regarded her with passion has passed. Some might argue, however, that referring to someone as an old flame means that while the relationship with that person is no longer current, the feeling of passion toward her persists. In other words, while the “flame” may be “old,” it has not yet “gone out.”
The exact origins of the expression “an old flame” are uncertain. Etymologists, or experts in the study of word origins, believe that the term has been in common usage since the mid-19th century, and perhaps even earlier. It is likely the expression emerged shortly after the word “flame” began to be commonly used to refer to a current love interest.