the third part of a month

[Larisa_rog]

What is the English for the third part of a month (i.e. 20th through 29th)? Is it correct to say "the 20s of a month"?

Thanks.

[JohnParis]

No, that would be incorrect to say "the 20's..."
There isn't (to my knowledge) a word or phrase that expresses the third week of the month other than simply saying "the third week of the month".
In business, you will often hear people referring to a week of the year by its number (there are 52 ). Today, we begin week 2 of 2012.
Week Numbers for 2012

[tedtmc]

I think the closest there is is early, mid and late January.

not a teacher

[BobSmith]

What is the English for the third part of a month (i.e. 20th through 29th)? Is it correct to say "the 20s of a month"?

Thanks.

[not a teacher]

Although valid (and you would be perfectly understood), I've never heard anyone refer specifically to the "third part" of a month. I think it would be understood if you used "the last third of the month", though I think it's more likely you'd hear "that last part of the month".

Slightly off-topic: I often hear my wife say "He's in his lower | upper 30's." (refering to age) when she actually means "He's in his early | late 30's". Always cracks me up*

*The funny part is that "upper" followed by a number range typically means temperature.

[SoothingDave]

It is typical to go by weeks, so there is no word for a 10 day period.

We might say "the third week of January" or "the week of the 16th" (naming the Monday starting the business week.)

[Larisa_rog]

Well, then, what about "third decade of the month"?

[SoothingDave]

No. Where does this need to divide a month into 10-day periods come from?

[Larisa_rog]

This is typical of Russia.

[SoothingDave]

Interesting. I'm afraid there is no term in English. I would go with the suggestion given above, to say the "last third" of the month.

[bhaisahab]

This may or may not be relevant but it's interesting.
For a brief period after the French revolution a new calender of ten-day weeks was introduced in France. There is some information about it here: French Republican Calendar - Wikipedia, the free encyclopedia