Apostrophe after “s” for possession with plural nouns Plural nouns that end in “s” (most plural nouns) form the possessive with an apostrophe after the “s,” without adding a second “s.” For example, to describe the roofs of multiple houses, you would write “the houses’ roofs” (“the house’s roofs” would refer to multiple roofs on one house).

Using an apostrophe to show plural possession Rule 2a. Regular nouns are nouns that form their plurals by adding either the letter s or es (guy, guys; letter, letters; actress, actresses; etc.). To show plural possession, simply put an apostrophe after the s.