A polysemy is a word or symbol that has more than one meaning. In order to be considered a polysemy, a word has to have separate meanings that can be different, but related to one another. The meanings and the words must have the same spelling and pronunciation and they must have the same origin.
The term polysemy is used in linguistics as a means of categorizing and studying various aspects of languages. Like many words used to categorize languages, polysemy is a mixture of Latin and Greek and means literally ‘many meanings.’ The opposite of a polysemy is a heterosemy, which means the word has only a single meaning.
Perhaps the word in English with the most meanings is ‘set.’ Dictionaries give ‘set’ around 120 meanings. English is filled with polysemic words with two, three or more meanings, including ‘wood,’ which means both part of a tree and a group of trees.
In order to be considered a polysemy, the word has to retain the same sound and the same spelling, but with distinct meanings. The difference between a polysemy and a homonym is difficult to determine. Homonyms also have the same spelling and the same pronunciation with different meanings. While the differences between homonyms and polysemes are subjective at best, however, it appears homonyms are words where the meanings have separate origins from one another.
The presumption with polysemes is that the different meanings all sprout from the same base word. This means their meanings have either splintered or evolved over time. Quite often, this occurs through the process of words changing form, such as nouns becoming verbs and vice versa. Slang and popular culture trends can also add meanings to words. For example, the word ‘gay’ meant ‘happy’ until the 20th century, when it also came to mean ‘homosexual.’
Other words have been polysemic, but now have had the number of meanings reduced by splitting words apart. One example of this is the difference between flour and flower. Flour was a polysemic word meaning both the grain used for bread and the flowers of plants. The word ‘flower’ was created to retain the same sound, but to distinguish the two meanings. In a twist, ‘flour’ has largely the one meaning, but ‘flower’ has taken on the meanings associated with the word ‘blossom’ as well to become a polysemy.
Polysemic words play a large role in comedy in the form of puns. A pun is a play on words where by a sentence, caption, title or joke plays on the fact that a word has more than one meaning. Puns can also play on the fact that a number of English words like ‘heir’ and ‘hair’ or ‘reign’ and ‘rain’ sound the same, but have different meanings. Polysemic puns play on the fact that the same spelling can produce different meanings.
Metonymy is also a form of polysemy. Metonymy occurs when a thing or place or group are known not by their official name, but by a single part. For example, if a car is called ‘wheels,’ it adds a new meaning to the world ‘wheel.’ This form of polysemy is not usually official, but is instead more of a slang formation. The practice of referring to governments by the name of the country’s capital city, for example, is a type of media shorthand.