I am trying to say the following:

I went to a birthday party. That birthday party was for my son's friend.

What possessive form should I use if I want to write it using the 's form?

My son's friend's birthday party


My son's friend birthday party

I know that this gets overly complicated and I am planning to use the initial, long form, but I am now curious to know what should be the correct way.

  • I think the first one is correct, without 's the possession is not specified
    – Ahmad
    Sep 26, 2016 at 19:52

1 Answer 1


The "longer" form is the only correct one.

Think of it this way: it's noun's birthday party. But noun doesn't have to just be a simple noun (like my son), it can also be a noun phrase (like the king of the moon or my son's friend), and 's will still go at the end. You would never say "friend birthday party" if it belongs to friend; it's always "friend's birthday party."

Don't be fooled by the fact that 's appears twice in "son's friend's birthday party"; the first one indicates that the friend belongs to your son, and the second one indicates that the party belongs to your son's friend. You can make this as long as you like - my uncle's barber's priest's next-door neighbor's grandson's roommate's girlfriend's sister's birthday party if you want - but the 's always has to get appended.

Reference: possession

  • Just for a better understanding: My son's friend's birthday party is correct, while My son's friend birthday party is not. Many thanks for the detailed answer and the useful link :)
    – fedorqui
    Sep 26, 2016 at 21:04

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