In linguistics, a homonym is, in the strict sense, one of a group of words that share the same spelling and the same pronunciation but have different meanings. Thus homonyms are simultaneously homographs (words that share the same spelling, regardless of their pronunciation) and homophones (words that share the same pronunciation, regardless of their spelling). The state of being a homonym is called homonymy. Examples of homonyms are the pair stalk (part of a plant) and stalk (follow/harass a person) and the pair left (past tense of leave) and left (opposite of right). A distinction is sometimes made between "true" homonyms, which are unrelated in origin, such as skate (glide on ice) and skate (the fish), and polysemous homonyms, or polysemes, which have a shared origin, such as mouth (of a river) and mouth (of an animal).
In non-technical contexts, the term "homonym" may be used (somewhat confusingly) to refer to words that are either homographs or homophones. In the stricter sense, the word row (propel with oars) and the American pronunciation of row (argument) are considered homonyms, as are the words read (peruse) and reed (waterside plant) in the looser sense.
The word homonym comes from the Greek ὁμώνυμος (homonumos), meaning "having the same name", which is the conjunction of ὁμός (homos), "common, same" and ὄνομα (onoma) meaning "name". Thus, it refers to two or more distinct concepts sharing the "same name" or signifier. Note: for the h sound, see rough breathing and smooth breathing.
Related terms 
|Homograph||Different||Same||Same or different|
|Homophone||Different||Same or different||Same|
|Polyseme||Different but related||Same||Same or different|
|Same except for
|Same or different|
Several similar linguistic concepts are related to homonymy. These include:
- Homographs (literally "same writing") are usually defined as words that share the same spelling, regardless of how they are pronounced.[note 1] If they are pronounced the same then they are also homophones (and homonyms) – for example, bark (the sound of a dog) and bark (the skin of a tree). If they are pronounced differently then they are also heteronyms – for example, bow (the front of a ship) and bow (a ranged weapon).
- Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.[note 2] If they are spelled the same then they are also homographs (and homonyms); if they are spelled differently then they are also heterographs (literally "different writing"). Homographic examples include rose (flower) and rose (past tense of rise). Heterographic examples include to, too, two, and there, their, they’re.
- Heteronyms (literally "different name") are the subset of homographs (words that share the same spelling) that have different pronunciations (and meanings).[note 3] Such words include desert (to abandon) and desert (arid region); row (to argue or an argument) and row (as in to row a boat or a row of seats - a pair of homophones). Heteronyms are also sometimes called heterophones (literally "different sound").
- Polysemes are words with the same spelling and distinct but related meanings. The distinction between polysemy and homonymy is often subtle and subjective, and not all sources consider polysemous words to be homonyms. Words such as mouth, meaning either the orifice on one's face, or the opening of a cave or river, are polysemous and may or may not be considered homonyms.
- Capitonyms are words that share the same spelling but have different meanings when capitalized (and may or may not have different pronunciations). Such words include polish (to make shiny) and Polish (from Poland); march (organized, uniformed, steady and rhythmic walking forward) and March (the third month of the year in the Gregorian Calendar). However, both polish or march at the beginning of sentences still need to be capitalized.
Further examples 
A further example of a homonym, which is both a homophone and a homograph, is fluke. Fluke can mean:
Similarly, a river bank, a savings bank, a bank of switches, and a bank shot in pool share a common spelling and pronunciation, but differ in meaning.
The words bow and bough are interesting because there are two meanings associated with a single pronunciation and spelling (the weapon and the knot); there are two meanings with two different pronunciations (the knot and the act of bending at the waist), and there are two distinct meanings sharing the same sound but different spellings (bow, the act of bending at the waist, and bough, the branch of a tree). In addition, it has several related but distinct meanings – a bent line is sometimes called a 'bowed' line, reflecting its similarity to the weapon. Thus, even according to the most restrictive definitions, various pairs of sounds and meanings of bow and bough are homonyms, homographs, homophones, heterophones, heterographs, and are polysemous.
- bow – a long wooden stick with horse hair that is used to play certain string instruments such as the violin
- bow – to bend forward at the waist in respect (e.g. "bow down")
- bow – the front of the ship (e.g. "bow and stern")
- bow – the weapon which shoots arrows (e.g. "bow and arrow")
- bow – a kind of tied ribbon (e.g. bow on a present, a bowtie)
- bow – to bend outward at the sides (e.g. a "bow-legged" cowboy)
- bough – a branch on a tree. (e.g. "when the bough breaks...")
Homonymy in historical linguistics 
See also 
- List of true homonyms
- Heterography and homography
- Synonyms, different words with identical or very similar meanings (conceptual inversion of "homonym")
- Some sources restrict the term "homograph" to words that have the same spelling but different pronunciations. See, for example, The Blackwell Encyclopedia of Writing Systems, p. 215 (Wiley-Blackwell, 1999) and The Encyclopaedia Britannica (14th Edition) (entry for "homograph").
- Some sources restrict the term "homophone" to words that have the same pronunciation but different spellings. See, for example, The Blackwell Encyclopedia of Writing Systems, p. 202 (Wiley-Blackwell, 1999) and The Encyclopaedia Britannica (14th Edition) (entry for "homograph").
- Some sources do not require that heteronyms have different pronunciations. See, for example, the archived Encarta dictionary entry (which states that heteronyms "often" differ in pronunciation) and the "Fun with Words" website (which states that heteronyms "sometimes" have different pronunciations).
- homonym, Random House Unabridged Dictionary at dictionary.com
- "Linguistics 201: Study Sheet for Semantics". Pandora.cii.wwu.edu. Retrieved 2013-04-23.
- Semantics: a coursebook, p. 123, James R. Hurford and Brendan Heasley, Cambridge University Press, 1983
- ὁμώνυμος, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus Digital Library
- ὁμός, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus Digital Library
- ὄνομα, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus Digital Library
- "The Online Etymological Dictionary". Retrieved 2008-01-14.
- On this phenomenon see Williams, Edna R. (1944), The Conflict of Homonyms in English, [Yale Studies in English 100], New Haven: Yale University Press, Grzega, Joachim (2004), Bezeichnungswandel: Wie, Warum, Wozu? Ein Beitrag zur englischen und allgemeinen Onomasiologie, Heidelberg: Winter, p. 216ff., and Grzega, Joachim (2001d), “Über Homonymenkonflikt als Auslöser von Wortuntergang”, in: Grzega, Joachim (2001c), Sprachwissenschaft ohne Fachchinesisch: 7 aktuelle Studien für alle Sprachinteressierten, Aachen: Shaker, p. 81-98.