Homonymy is a linguistic phenomenon that has a peculiarity: the similarity between two words. This similarity has two variants, homophony and homography.
In this sense, it is worth clarifying the etymological meaning of these terms
Homonymy comes from the Greek homo which means equal. Thus, there are two terms that are the same, as nímia comes from nomos that means name. However, there is not only one form of homonymy. There is homography that comes from homo and grafia that means writing (like geography or calligraphy) and also homophony that has the prefix homo followed by phonia that means sound.
Based on this etymological clarification, it is important to illustrate these ideas with some examples in their two variations: homographic homonym and homophone homonym
In the first case, it can be said that they are written in the same way, but they have a different meaning and pronunciation, for example, seat of will and seat of residence; ice being a noun and ice from the verb to freeze. Homonymy, on the other hand, is homophone when two words are pronounced in the same way, but their writing is different, for example, walnut and knots; concert and repair.
Homonymy has the peculiarity that the words compared in any of its senses have nothing in common, that is, their etymological origin is totally different, since both terms do not have the same root and evolution , although their development process manifest a similarity between the two. In this sense, when speaking of homonymy, there is always a comparison between two words. There is a phenomenon that is sometimes confused with homonymy: it is polysemy. It consists of a certain word or expression acquiring a new meaning beyond its original meaning, keeping a relationship of meaning between them. For example: “I left them with their mouths open”. “The mouth of the bottle is broken”.
Homonymy and polysemy are distinct phenomena that are often confused or even presented as equivalent. Homonymy has an opposite concept, synonymy has two different words with the same meaning and polysemy has monosemy as an antagonistic idea, that is, when a word has only one meaning.