At five o'clock

[moseen]

Hello everybody!
in the sentence below, is "five o'clock" countable or uncountable? why doesn't it have "the"?

I'll see you at five o'clock.

 

[GoesStation]

It's uncountable. We don't use the definite article in the construction x o'clock except when the time phrase is used as a modifier* as in the five o'clock news.

*In my example, "five o'clock" modifies news.

 

[moseen]

We don't use the definite article in the construction x o'clock.

*In my example, "five o'clock" modifies news.

Is there nothing to do with it is uncountable?

 

[bubbha]

No. "o'clock" is not a noun.

 

[moseen]

No. "o'clock" is not a noun.

What is it?

 

[Roman55]

It's an adverb.

 

[moseen]

It's an adverb.

What is "five"?

 

[Matthew Wai]

It is a number.

 

[moseen]

It is a number.

So what is noun?

 

[Matthew Wai]

The adverb 'o'clock' modifies the number 'five'.

 

[moseen]

The adverb 'o'clock' modifies the number 'five'.

if "five o'clock isn't" a noun, why does it have "at"? Why did GoesStation say it is uncountable?

 

[GoesStation]

No. "o'clock" is not a noun.

Good point. Like all words that aren't nouns, "o'clock" is neither countable nor uncountable.

 

[moseen]

Good point. Like all words that aren't nouns, "o'clock" is neither countable nor uncountable.

If it isn't a noun, why does it have "at"?

 

[Matthew Wai]

'Five' is the object of 'at'.

 

[Tdol]

If it isn't a noun, why does it have "at"?

If we use at once, is once a noun to you?

 

[moseen]

'Five' is the object of 'at'.

'Five' is definite, why doesn't it have "the"?

 

[moseen]

If we use at once, is once a noun to you?

No, once is an adverb but "at once" is always together, it seems like one word, no?

 

[Matthew Wai]

'Five' is definite, why doesn't it have "the"?

I take 'at five o'clock' to mean 'at the time when it is five o'clock', where 'the time when it is' can be omitted.
Are you going to ask why 'the' is not needed in 'it is five o'clock'?

 

[moseen]

I take 'at five o'clock' to mean 'at the time when it is five o'clock', where 'the time when it is' can be omitted.
Are you going to ask why 'the' is not needed in 'it is five o'clock'?

No, but...

 

[moseen]

No, but...

I could find my answer here:
we don't use articles before numbers.
http://grammar.ccc.commnet.edu/grammar/determiners/determiners.htm

When they do not come before a noun, numerals are a subclass of nouns. And like nouns, they can take determiners:
the two of us
the first of many
Reference: http://www.ucl.ac.uk/internet-grammar/determin/numerals.htm