Meaning of "thisweek" and "lastweek" in search syntax

[burgundy]

I am a bit confused about how to use these terms when searching: <last|past|prev|current|this|coming|next><year|month|week>

"WEEK" --- Is the term "week" used in the sense of always having a defined starting day? Such as Sunday or Monday.

"LAST" --- Does "lastweek" mean the last 7 days counted from today OR does it mean the most recent period of 7 days that begins with the defined starting day?

"THIS" --- Does "thisweek" also mean the last 7 days counted from today OR does it mean the week so far up to today, starting from the defined starting day?

[void]

"WEEK" --- Is the term "week" used in the sense of always having a defined starting day? Such as Sunday or Monday.

Yes.
The starting date of the week is determined by your Windows setting "First day of week", which can be found in the Control Panel, under Region and Language, under the Formats tab.

"LAST" --- Does "lastweek" mean the last 7 days counted from today

No

OR does it mean the most recent period of 7 days that begins with the defined starting day?

Yes, exactly.

"THIS" --- Does "thisweek" also mean the last 7 days counted from today

No.

OR does it mean the week so far up to today, starting from the defined starting day?

Yes.

If you want to search for the last 7 days, use the time syntax: last7days
For example: files modified in the last 7 days:
dm:last7days

[burgundy]

After some time using these modifiers, I would like to request a change.

This is the current situation:
"this month" means this current calendar month.
"last month" means the previous calendar month.
"last2months" means the previous calendar month plus the calendar month before that.

However "last2months" tends to suggest a meaning of going back 60 days from today. It is very unusual for it to mean the two calendar months before the current one but not the days in the current calendar month.

In this respect the meaning for "last2months" can't really be compared to the meaning for "lastmonth".

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(1) Of course this also applies to "weeks". "last2weeks" currently goes up to Sunday but not from Monday to today. It sounds odd!

(2) "last2years" works as expected and, unlike "weeks" or "months", includes this year

(3) "days" doesn't really have this distinction

[therube]

(I'm on XP.)

No big deal, but I'll note that some searches turn up "future" dates.
(Yes, I have some.)

On my end, I'm not sure what last2months (or last2month, singular) are giving me?

Today (being 11-15-2017)...

last2month, is giving me files dated 11-06-2017, so maybe that is 1 week minus 2?
last2months, is giving me; future files (don't particularly care about that) - oh, I see, its giving me 2 months back from today.

And that's different from what burgundy describes:

"last2months" means the previous calendar month plus the calendar month before that.

(Suspect there is something OS going on here.)

[void]

lastmonth and last<x>months have different meanings.

lastmonth = Was the file modified last month?
last<x>months = Was the file modified in the last <x> months from now?

Currently, today being 17/11/2017, last2months matches 17/9/2017 - end of times.
Today being 17/11/2017, lastmonth matches 1/10/2017 - 31/10/2017.

Would you prefer last<x>months matched the last 2 whole months, excluding the current month?
For example, today being 17/11/2017, last2months would match 1/9/2017 - 31/10/2017.

[burgundy]

I have got a bit lost with what was happening here! When I get a moment i will review it all again in the light of comments from TheRube.