possessive case

omistussija puhekieltä: case used to express direct possession, ownership, origin, etc. Though similar in many ways to the genitive case, it is not always the same. Languages that have the possessive case include English and Quenya.
1784, An Essay towards an English Grammar. With a Dissertation on the Nature and peculiar Use of certain Hypothetical Verbs, in the English Language. London, p.5 & p.83:

Substantives in the English tongue, have only two terminations for case: the nominative, which merely expresses the name of the thing, and the possessive, or genitive case, made by the addition of s, with an apostrophe before it, which denotes property: all other realtions between substantives, as this also very often, are expressed by different prepositions: for example---a freeman's rights''; or the rights of a freeman.

When one thing is expressed as belonging to another, then one of the substantives is said to govern the other in the genitive, or possessive case; thus, Miltons poems; the king's gift; William's book. Here the former substantive, ending in 's, marked with an apostrophe, is the word governed; as Milton's: the latter is the word that governs; as, poems: the former is in the genitive case, which is marked thus, 's, which mark is called the possessive 's.