In English, possessive words or phrases exist for nouns and most pronouns, as well as some noun phrases. These can play the roles of determiners (also called possessive adjectives when corresponding to a pronoun) or of nouns.
Nouns, noun phrases and some pronouns generally form a possessive with the suffix -'s (or in some cases just by adding an apostrophe to an existing -s). This form, particularly in English language teaching, is sometimes called the Saxon genitive, reflecting the suffix's derivation from a genitive case ending in Old English (which in older scholarship was known as Anglo-Saxon). Personal pronouns, however, have irregular possessives, and most of them have different forms for possessive determiners and possessive pronouns, such as my and mine or your and yours.
Possessives are one of the means by which genitive constructions are formed in modern English, the other principal one being the use of the preposition of. It is sometimes stated that the possessives represent a grammatical case, called the genitive or possessive case, though many linguists do not accept this view, regarding the -'s ending as a clitic rather than as a case ending.
Formation of possessive construction 
Nouns and noun phrases 
The possessive form of an English noun, or more generally a noun phrase, is made by suffixing a morpheme which is represented orthographically as 's (the letter s preceded by an apostrophe), and is pronounced in the same way as the regular English plural ending -(e)s: namely as /ɨz/ when following a sibilant sound (/s/, /z/, /ʃ/, /ʒ/, /tʃ/ or /dʒ/), as /s/ when following any other voiceless consonant (/p/, /t/, /k/, /f/ or /θ/), and as /z/ otherwise. For example:
- Mitch /mɪtʃ/ has the possessive Mitch's /ˈmɪtʃɨz/
- luck /lʌk/ has the possessive luck's /lʌks/
- man /mæn/ has the possessive man's /mænz/
Note the distinction from the plural in nouns whose plural is irregular: man's vs. men, wife's vs. wives, etc.
In the case of plural nouns ending in -s, and in the case of certain other nouns ending in -s, the possessive is indicated in writing just by adding an apostrophe, and is not indicated in the pronunciation:
- the possessive of cats is cats', both words being pronounced /kæts/
- the possessive of Jesus is most commonly Jesus', both words being pronounced /ˈdʒiːzəs/
Singular nouns ending in -s can also form a possessive regularly by adding -'s, as in Charles's /ˈtʃɑː(r)lzɨz/. The Chicago Manual of Style recommends this more modern style, while stating that adding just an apostrophe (e.g. Jesus') is also correct. The Elements of Style and the Canadian Press Stylebook prefer the form in -s's with the exception of classical and Biblical proper names (Jesus' teachings, Augustus' guards) and common phrases that do not take the extra s (e.g. "for goodness' sake"). For more on style guidance for this and other issues relating to the construction of possessives in English, see Possessive apostrophe.
More generally, the -'s morpheme can be attached finally to noun phrases, even if the head noun does not end the phrase. For example, the phrase the king of Spain can form the possessive the king of Spain's, and the phrase the man we saw yesterday can form the man we saw yesterday's. This property is taken as evidence that -'s is a clitic rather than a case ending; see Status of the possessive as a grammatical case below.
Unlike with other noun phrases which only have a single possessive form, personal pronouns in English have two possessive forms: possessive determiners (used to form noun phrases such as "her success") and possessive pronouns (used in place of nouns as in "I prefer hers", and also in predicative expressions as in "the success was hers"). In most cases these are different from each other.
For example, the pronoun I has possessive determiner my and possessive pronoun mine; you has your and yours; he has his for both; she has her and hers; it has its for both (though rarely used as a possessive pronoun); we has our and ours; they has their and theirs. The archaic thou has thy and thine. For a full table and further details, see English personal pronouns.
Note that possessive its has no apostrophe, although it is sometimes written with one in error, by confusion with the common possessive ending -'s and the contraction it's used for it is and it has. Possessive its was originally formed with an apostrophe in the 17th century, but this was dropped in the early 19th century, presumably to make it more similar to the other personal pronoun possessives.
The interrogative and relative pronoun who has the possessive whose. In its relative (but not interrogative) use, whose can also serve as a possessive of which (i.e. to refer to things and abstracts as well as people).
Other pronouns that form possessives (mainly indefinite pronouns) do so in the same way as nouns, with -'s, for example one's, somebody's (and somebody else's). Certain pronouns, such as the demonstratives this, that, these, those, do not have possessive forms.
Syntactic functions of possessive words or phrases 
English possessives play two principal roles in syntax:
- the role of possessive determiners (more popularly called possessive adjectives; see Possessive: Terminology) standing before a noun, as in my house or John's two sisters;
- the role of possessive pronouns (although they may not always be called that), standing independently in place of a noun, as in mine is large; they prefer John's.
As determiners 
Possessive noun phrases such as "John's" can be used as determiners. When a form corresponding to a personal pronoun is used as a possessive determiner, the correct form must be used, as described above (my rather than mine, etc.).
Possessive determiners are not used in combination with articles or other definite determiners. For example, it is not correct to say *the my hat, *a my hat or *this my hat; an alternative is provided in the last two cases by the "double genitive" as described in the following section – a hat of mine (also one of my hats), this hat of mine. Possessive determiners can nonetheless be combined with certain quantifiers, as in my six hats (which differs in meaning from six of my hats). See English determiners for more details.
A possessive adjective can be intensified with the word own, which can itself be either an adjective or a pronoun: my own (bed), John's own (bed).
In some expressions the possessive has itself taken on the role of a noun modifier, as in cow's milk (used rather than cow milk). It then no longer functions as a determiner; adjectives and determiners can be placed before it, as in the warm cow's milk, where idiomatically the and warm now refer to the milk, not to the cow.
Possessive relationships can also be expressed periphrastically, by preceding the noun or noun phrase with the preposition of, although possessives are usually more idiomatic where a true relationship of possession is involved. Some examples:
- the child's bag might also be expressed as the bag of the child
- our cats' mother might be expressed as the mother of our cats
- the system's failure might be expressed as (the) failure of the system
Another alternative in the last case may be (the) system failure, using system as a noun adjunct rather than a possessive.
As pronouns 
Possessives can also play the role of nouns or pronouns; namely they can stand alone as a noun phrase, without qualifying a noun. In this role they can function as the subject or object of verbs, or as a complement of prepositions. When a form corresponding to a personal pronoun is used in this role, the correct form must be used, as described above (mine rather than my, etc.).
- I'll do my work, and you do yours. (here yours is a possessive pronoun, meaning "your work", and standing as the object of the verb do)
- My car is old, Mary's is new. (here Mary's means "Mary's car" and stands as the subject of its clause)
- Your house is nice, but I prefer to stay in mine. (here mine means "my house", and is the complement of the preposition in)
A notable construction is that of the type a friend of mine, two books of John's, where of plus a possessive pronoun effectively means "out of all of mine/John's". Logically of me and of John might be expected, but these are usually less idiomatic. (Alternative phrasings are one of my friends and two of John's books.) This is sometimes called the double genitive, double possessive or oblique genitive. Some regard it as a questionable usage, although it has a history in careful English, and there is sometimes no idiomatic alternative. It is generally confined to human referents: a friend of the Gallery would be used rather than ...of the Gallery's. Its use sometimes resolves ambiguity, as in a picture of the king’s (one owned by the king), as distinct from a picture of the king (one portraying the king).
In predicative expressions 
When they are used as predicative expressions, as in this is mine and that pen is John's, the intended sense may be either that of a pronoun or of a predicate adjective; however their form (mine, yours, etc.) in this case is the same as that used in other sentences for possessive pronouns.
Use of whose 
The following sentences illustrate the uses of whose:
- As the possessive of interrogative who: Whose pen is this? Whose do you prefer? For whose good is this being done?
- As the possessive of relative who (normally only as determiner, not pronoun): This is the man whose pen we broke. That is the woman in whose garden you woke up.
- As the possessive of relative which (again, normally only as determiner): It is an idea whose time has come (alternatively ...of which the time has come).
Possessives, as well as their synonymous constructions with of, express a range of relationships that are not limited strictly to possession in the sense of ownership. Some discussion of such relationships can be found at Possession (linguistics) and at Possessive: Semantics. Some points as they relate specifically to English are discussed below.
When possessives are used with a verbal noun or other noun expressing an action, the possessive may represent either the doer of the action (the subject of the corresponding verb) or the undergoer of the action (the object of the verb). The same applies to of phrases. When a possessive and an of phrase are used with the same action noun, the former generally represents the subject and the latter the object. For example:
- Fred’s dancing (or the dancing of Fred) – Fred is the dancer (only possible meaning with this verb)
- the proposal's rejection or the rejection of the proposal – the proposal is rejected
- Fred's rejection of the proposal – Fred is the rejecter, the proposal is rejected
Time periods 
Time periods are sometimes put into possessive form, to express the duration of or time associated with the modified noun:
- the Hundred Years’ War
- a day's pay
- two weeks’ notice
The paraphrase with of is often un-idiomatic or ambiguous in these cases.
Expressing for 
Sometimes the possessive expresses who the thing is for, rather than to whom it belongs:
- women’s shoes
- children’s literature
These cases would be paraphrased with for rather than of (shoes for women).
Appositive genitive 
Sometimes genitive constructions are used to express a noun in apposition to the main one, as in the Isle of Man, the problem of drug abuse. This may be occasionally be done with a possessive (as in Dublin’s fair city, for the fair city of Dublin), but this is a rare usage.
The 's morpheme originated in Old English as an inflexional suffix marking genitive case. In the modern language, it can often be attached to the end of an entire phrase (as in "The King of Spain's wife" or "The man whom you met yesterday's bicycle"). As a result, it is normally viewed by linguists as a clitic, i.e. a morpheme that cannot be a word by itself but is grammatically independent of the word it is attached to, as in forms such as 'm (as in I'm) or n't (as in don't). 
A similar form of the morpheme existed in the Germanic ancestor of English, and exists in some modern Germanic languages.
In Old English, -es was the ending of the genitive singular of most strong declension nouns and the masculine and neuter genitive singular of strong adjectives. The ending -e was used for strong nouns with Germanic ō-stems, which constituted most of the feminine strong nouns, and for the feminine genitive singular form of strong adjectives.
|Weak||m. / f. / n.||-an||-ena|
In Middle English the -es ending was generalised to the genitive of all strong declension nouns. By the sixteenth century, the remaining strong declension endings were generalised to all nouns. The spelling -es remained, but in many words the letter -e- no longer represented a sound. In those words, printers often copied the French practice of substituting an apostrophe for the letter e. In later use, -'s was used for all nouns where the /s/ sound was used for the possessive form, and the -e- was no longer omitted. Confusingly, the -'s form was also used for plural noun forms. These were derived from the strong declension -as ending in Old English. In Middle English, the spelling was changed to -es, reflecting a change in pronunciation, and extended to all cases of the plural, including the genitive. Later conventions removed the apostrophe from subjective and objective case forms and added it after the -s in possessive case forms. See Apostrophe: Historical development
Another remnant of the Old English genitive is the adverbial genitive, where the ending -s (without apostrophe) forms adverbs of time: nowadays, closed Sundays. There is a literary periphrastic form using of, as in of a summer day. There are also forms in -ce, from genitives of number and place: once, twice, thrice; whence, hence, thence.
There is also the "genitive of measure": forms such as "a five-mile journey" and "a ten-foot pole" use what is actually a remnant of the Old English genitive plural which, ending in /a/, had neither the final /s/ nor underwent the foot/feet vowel mutation of the nominative plural. In essence, the underlying forms are "a five of miles (O.E. gen. pl. mīla) journey" and "a ten of feet (O.E. gen. pl. fōta) pole".
Status of the possessive as a grammatical case 
English possessives are sometimes said to represent a grammatical case, called the "possessive case" or "genitive case". Historically, the possessive morpheme represented by -'s was a case marker, as noted in the previous section. In Modern English, however, many grammarians consider it to be a clitic rather than a case ending. This is evidenced by phrases like the king of England's horse – if the -'s were a true case ending, it would be expected on king rather than England (*the king's of England horse), since the horse belongs to the king and not to England. (Compare the German das Pferd des Königs von England, where König "king" takes the genitive case. Older English provides constructions like the King's dochter of Noroway, from the ballad "Sir Patrick Spens", meaning "the daughter of the King of Norway".)
Because the ending is in fact separable from the head noun (king) and attaches to the noun phrase as a whole, it is more likely to be analyzed as a clitic. It is claimed that traditional grammarians are uncomfortable with this analysis because they like to view English grammar through the lens of classical languages like Latin and Ancient Greek, which had well-developed case systems.
- The Chicago Manual of Style
- The Elements of Style
- The Canadian Press Stylebook, 14th Edition. ISBN 978-0-920009-42-0.
- The Oxford English Dictionary says that this usage was "Originally partitive, but subseq. ... simple possessive ... or as equivalent to an appositive phrase ...". "of XIII.44". The Oxford English Dictionary 10 (2 ed.). Oxford: Clarendon Press. 1989. p. 715. ISBN 0-19-861186-2.
- Huddleston, Rodney; Pullum, Geoffrey K. (2002). "5: Nouns and noun phrases § 16.3 Type III". The Cambridge Grammar of the English Language. Cambridge: Cambridge University Press. pp. 468–9. ISBN 0-521-43146-8.
- Quinion, Michael. "Double Possessive". World Wide Words. Retrieved 2009-05-19.
- "Moreover, in some sentences the double genitive offers the only way to express what is meant. There is no substitute for it in a sentence such as That’s the only friend of yours that I’ve ever met, since sentences such as That’s your only friend that I’ve ever met and That’s your only friend, whom I’ve ever met are not grammatical." American Heritage Book of English Usage: A Practical Guide to Contemporary English. Boston: Houton Mifflin. 1996. p. 26. ISBN 0-395-76786-5.
- page 162 under the heading double genitive in Pam Peters (2004). The Cambridge Guide to English Usage. Cambridge: Cambridge University Press. ISBN 0-521-62181-X.
- Fowler, Henry W.; Burchfield, R.W. (2000). "double possessive". The New Fowler’s Modern English Usage (revised third ed.). Oxford: Oxford University Press. p. 227. ISBN 0-19-860263-4.
- Quirk, Randolph; Greenbaum, Sidney; Leech, Geoffrey; Svartvik, Jan (1985). "§ 5.116 note [b]". A Comprehensive Grammar of the English Language. London and New York: Longman. p. 322. ISBN 0-582-51734-6.
- Is the English Possessive 's Truly a Right-Edge Phenomenon?
- Campbell, A. Old English Grammar. Oxford University Press. Oxford 1959. Chapter IX
- "adverbial genitive". Merriam-Webster’s Dictionary of English Usage. Springfield, MA: Merriam-Webster. 1994. pp. 35–6. ISBN 978-0-87779-132-4. Retrieved 2009-05-16. "Also see entry of.3 page 680."
- The Origins and Development of the English Language, Volume 1, John Algeo, Thomas Pyles Cengage Learning, 2009, p 96
- Payne, John & Rodney Huddleston. 2002. Nouns and noun phrases. In Rodney Huddleston & Geoffrey K. Pullum (eds.), The Cambridge grammar of the English language, 323–523. Cambridge: Cambridge University Press. ISBN 0-521-43146-8. (Relevant section is pp. 479–481.)