“One of my friends” vs. “one of my friend”

Question

Which of the following is correct?

1. Yesterday, I met one of my friends.
2. Yesterday, I met one of my friend.

Answer 1

It's "one of my friends". The other option would be ungrammatical.

To spice it up a little, here are the stats from the Corpus of Contemporary American English and the British National Corpus:

                     COCA    BNC
one of my friends     251     40
one of my friend        0      0
one of your friends    58      6
one of your friend      0      0
one of our friends     40      7
one of our friend       0      0
one of his friends    182     60
one of his friend       0      0

Answer 2

Wouldn't you rather say "a friend of mine"?

Answer 3

Think of it this way: If you didn't have several friends, you wouldn't need to be specifying that you only met one friend. "One of" is indicating a particular member out of a set with multiple members in it, so it's correct to use the plural form: "One of my friends." If you only have one friend total, then you can just say "Yesterday, I met my friend."

Similarly, when you turn it around thus:

One of my friends is meeting me later

then it's correct to use the singular verb form, because you're still only talking about one person. (Many people get confused because "friends", plural, is right next to the verb "is", but "One" is the true subject of the sentence.)

Answer 4

With the exception of (eventual) set phrases, when you say one of [noun], [noun] is used in the plural form.