2.180 Indicating possession or association: possessive structures

One way of specifying something is by saying who or what it belongs to or is associated with. So that, for example, you can talk about 'Elizabeth's book', or 'the teacher's role'.

This section deals with ways of expressing possession within a noun group, typically by using a structure based on apostrophe s ('s). When apostrophe s ('s) is added to a noun or name it is called the possessive form; some grammars call it the genitive.