enough + singular noun

[aysaa]

Hello,

Use of enough

enough - Definition from Longman English Dictionary Online

!! Nouns used with enough must be plural or uncountable, never singular

• There aren't enough books (NOT enough book).

Is there any exception in this usage? I have seen some sentences in which a singular noun has been used with enough.

There is enough room for everbody to sit down.
There is not enough room to swing a cat.

Thanks...

[5jj]

'Room' is uncountable in that sense.