# Why is it "time of day" but "hour of the day"?

Well, the title is a little misleading, because both "time of day" and "time of the day" are possible and can have the same meaning.[here] But "time of day" is more commonly used (when we're not mentioning a particular day, of course):

So you're more likely to hear:

We love to eat around this time of day.

But after we substitute "hour" for "time", the article is almost always in there:

So the previous example would become:

We love to eat around this hour of the day.

I imagine that native speakers of English would agree that it sounds a little off (or at least less natural) to say: ?We love to eat around this hour of day.

These 2-grams† bellow will show that the tendency to omit the definite article after time of exists in other similar phrases too:

or bigrams, or n-grams, if you will

To complicate things further, take a look at this 2-gram, which tells you that any time of the day is a little more common than any time of day; i.e., adding any kinda swaps the results around!
I guess this is because you're more likely to talk about a nonspecific time of a specific day, than to talk about any time of any day, for there is not much to say about it; hence the definite article before day.

• My speculation is that you say time of X (X being a time period) when you want to refer to a natural stage or segment of X (e.g., noon as a section of (a general) day, or spring as a segment of (a general) year). The use of zero article indicates that it's the general concept of day, year, etc. you're talking about, not a specific day, and not even a nonspecific day. But this is not possible in hour of the day or day of the month, because a day is not naturally divided into hours, nor is a month into days.
– Færd
Commented Feb 12, 2016 at 15:30
• First, I am puzzled as to why you include at in your second example - eat around at this hour of the day rather than eat around this hour of the day. I speak from a British perspective when I say that that alone seems foreign. Otherwise I am in agreement with the different idiomatic forms you quote. Interestingly, were we talking about night, it would not be unusual to hear What are you doing here at this hour of night - no article! These idiosyncrasies are a bit like accents, there is no doubting they exist, but their origins may be lost in the mists of time.
– WS2
Commented Feb 12, 2016 at 15:50
• All those inclusions of at which you quote are perfectly correct. But in your previous examples you put it following around. Both around and at are prepositions and you don't need two of them. Either one or the other would have been grammatically correct, though they each supply their own meaning.
– WS2
Commented Feb 12, 2016 at 18:14
• @WS2 Oh my, you're right! Thanks. I thought 'to eat around' was a phrasal verb.
– Færd
Commented Feb 12, 2016 at 18:40
• I did think of that possibility. There may be people who use eat around as a phrasal verb, in which case the at would be justified. Perhaps there are Americans who say that - but you would be unlikely to hear it in Britain. Of course you can mess around or fool around AT any hour of the day!
– WS2
Commented Feb 12, 2016 at 19:09

I think that the difference is simply that "time" is not specific, whereas "hour", "day" or "month" refer to fixed amounts of time.

So time of day/month/year is a more general expression and "day of the year" or "hour of the day" are more specific, despite being sometimes used interchangeably as in "time of day" and "hour of the day".

Example :

This time of year gets very rainy / This month of the year gets 150cm of rain on average

I get sleepy this time of day / I like to take my medication at this hour of the day.

The plausible explanation may be in the axiom, "Time and tide waits for none". They are ever flowing. Ask a philosopher and he will tell you that the stream you are bathing or the flame of the candle keep on changing ever.

So to this ever changing concept of time we put the physical boundary of hours, years, days or months. So the time of day is non specific, hours specific.Hence, when we substitute 'hour' for 'time', the abstact concept of 'time' is arrested in countable minutes, seconds, days and years. Specific in relation to specific requires placing of a definite/indefinite article. This is the general prescription. We use it without our conscious effort.

However, when we say 'any time of the day' we are actually thinking not in terms of the abstract concept of time but in terms of time as we have devised it in compartments.

• Your answer doesn't explain the use of definite or zero article before day, which was my point of interest.
– Færd
Commented Feb 25, 2016 at 2:46