s
/ĕs/
noun
- The 19th letter of the modern English alphabet.
- Any of the speech sounds represented by the letter s.
- The 19th in a series.
Both express possession, of course.
We use 's with singular nouns. For example, "my son's toys" will be "the toys that belong to my son".
We use only an apostrophe (') after plural nouns that end in -s: "my sons' toys" means that I have more than one son and these are their toys.
We use 's for possession with the other plural nouns. For example: "my children's toys; women's wishes, etc.
Answer from fluffy on Stack ExchangeIs its or it’s possessive?
When do you use its vs. it’s?
Videos
Both express possession, of course.
We use 's with singular nouns. For example, "my son's toys" will be "the toys that belong to my son".
We use only an apostrophe (') after plural nouns that end in -s: "my sons' toys" means that I have more than one son and these are their toys.
We use 's for possession with the other plural nouns. For example: "my children's toys; women's wishes, etc.
Fluffy's answer is correct about the possessive usages, so I won't repeat those. However, it misses an important point.
Possession isn't the only use for 's; it can also be a contraction for is. For example: it's, how's, he's, she's, that's, etc. In standard English, s' is never a contraction*.
The double meaning of 's leads to one of the most common mistakes in written English: confusing its, which is the possessive form of it, and it's, which is a contraction of it is.
* - When approximating certain dialects or slang in writing, s' may be used, rarely, as an abbreviation or contraction of it is when placed at the front (never the back!) of another word. For example, there's a famous comedy puppetry bit which makes heavy use of s'alright to mean it's alright. However, this is absolutely neither standard nor something you should emulate.