For example, Sue’s book, or the table’s legs. When the possessor’s name already ends in an s (or s sound ie z, x, se, ce, ze or xe), the ‘s is usually retained but can be omitted if it makes the word or phrase awkward to say, ie James’s or Julius’s but Williams’ or especially Moses’ or Socrates’ where there’s already an es type sound at the end of the word; however Chris's and Jesus's are used.
When the possessor is plural the s after the apostrophe is always omitted, eg the tables’ legs, boys’ game or bosses’ room.
The words its, theirs, ours, whose, yours and hers (also his and mine, from hes and mys) are already fixed as possessive and don’t have apostrophes: hence it’s and who’s are always abbreviations.The singular one's, somebody's, nobody else'sand also everyone's however take apostrophes, but never s’.
Men, women and children are also plural and to make them possessive, ‘s is added, eg women’s hats. s’ is never added, and chilrens, mens and womens also aren’t words. However though people is likewise already plural, s’ is used in refering to a number of peoples, eg the African peoples’ languages- and peoples is a word, as though a plural plural. Persons’ is also possible.
An s of course is also added to verbs without an apostrophe to denote third person possession, eg she thinks, he takes or it begins.
Names of companies may or may not use the apostrophe, eg Lloyds Bankdoesn’t but Sainsbury’s does- it may be removed when there’s no association with the company’s originators and the word becomes just a title; similarly the apostrophe is usually omitted in geographical names, eg Smiths canyon.
Possessors ending in a letter of an s sound that isn’t sounded can have an apostrophe without an s after it to indicate that the previous letter should be sounded, eg Descartes' ideas.
Ineg for convenience' sake or for goodness' sake the s after the apostrophe can be omitted because although these possessors aren’t plural they end with the s sound and are followed by a word beginning with s sound; proper nouns however, eg James’s sake, still retain it.
Where there is more than one possessor the apostrophe goes only after the last one mentioned, eg John and Sue’s party.
Apostrophes are needed in one hour's work, two weeks' holiday, and five dollars’ worth.
Abbreviating the i in is and leaving only the s at the end of the previous word can look superficially like possession, eg My name’s Sean.
Apostrophes are usually omitted when letters are removed from the start of a word, eg phone for telephone or netfor internet, other than when the shortening is less standard English, eg 'bout for about, or 'less for unless.
The apostrophe is not used to mark plurality, apart from cases like capital S’s or number 1’s, being clearer than Ss or 1s, even though this would normally denote possession by the S or 1; similarly dot your i's and cross your t's, grade A’s or yes’s, no’s, do’s and ex’s.Apostrophes can further be used to clarify the endings of unusual words, such as n'th rather than nth.
Passers-by,Attorneys General or rites of passage are examples of a possessor where the plural s is not placed on the end word, complicating placing of apostrophes.
Moreover the apostrophe is distinct from the same 9-shaped punctuation mark for closing a quotation, or marking feet and inches or minutes and seconds of degrees.
The apostrophe has numerous other minor uses.