In the second group of phrases (“a moment’s pause,” etc.), the possessive denotes not ownership, but measure or extent.

IV. The possessive case of certain pronouns (my, our, your, his, her, its, their) is more freely used than that of nouns in expressions that do not denote actual ownership.

For the inflection of these pronouns, see [§ 115]. For the use of whose, see [§ 152].

94. When a thing belongs to two or more joint owners, the sign of the possessive is added to the last name only.

95. In compound nouns the last part takes the possessive sign. So also when a phrase is used as a noun.

Other examples are the following:—