plural nouns: should I add "s" ending to both nouns? [duplicate]

Is it correct to say user accounts or users account when referring to the accounts any user has on a site like this one?

In general, in the case of a noun that is used as adjective for the noun that follows, is it better to use <plural-noun> <singular-noun> or <singular-noun> <plural-noun>?

Solution 1:

<singular-noun> <plural-noun>

is the way to go.

Solution 2:

Use user account for one account and user accounts for many accounts.

This is a compound noun with account modified by user. In such cases, we use the singular form of the first noun. Other examples are car keys and house windows.

Solution 3:

You seem to have answered you own question.

"... when referring to the accounts any user has on a ..."

One user. Multiple accounts. "User accounts". "Users Account," while not meaning anything at all, sounds like multiple users are using one account—or like "Brothers Grimm..." but that doesn't work in the same way.