In his book Write It Right, which was published in 1909 -– a hundred years ago -- Ambrose Bierce disagreed with the usage of the words “Last” and “Past” with “week”. He explained :
Last and Past. “Last week.” “The past week.” Neither is accurate: a week cannot be the last if another is already begun; and all weeks except this one are past. Here two wrongs seem to make a right: we can say the week last past. But will we? I trow not.
And H. W. Fowler agreed with those sentiments in his Fowler's Modern English Usage 1st Ed.
4. Last) (latest. In this now favourite antithesis (Dr Marshall's latest, but we hope not his last, contribution) we are reminded that latest means last up to now only, whereas last does not exclude the future. The distinction is a convenient one, & the use of latest for last is described by the OED as ' now archaic & poetical'. But no corresponding agreement has yet been reached for abstaining from last when latest would be the more precise word, & many idioms militate against it (last Tuesday; last year ; for the last fortnight; on the last occasion ; as I said in my last).
And his successor, R. W. Burchfield, also agreed, in New Folwer's Modern English Usage 3rd Ed.
4. Last/Latest. In such a context as “In his latest book, Dr. A…”, it is clear that Dr. A has written earlier books and that he is still alive and may well write others. If the statement runs “In his last book, Dr A…” the meaning could be the same, or it could also imply that this was the final book written by Dr A before he died. It is obvious, therefore, that if there is any danger of contextual ambiguity some word other than last should be used. In many idiomatic phrases last is still the only possible adj. of the two: = most recent; next before a specified time ( last Christmas; last week); = preceding; previous in a series ( got on at the last station); = only remaining ( the last biscuit; our last chance); ( preceded by the) = the least likely or suitable ( the last person I’d want to see; the last thing I’d have expected; = the lowest in order ( the last name on the list).
Nevertheless, the Oxford English Dictionary 2nd Ed described yester as:
in comb. or as prefix = immediately preceding the present, last, in yestereve, etc., after yesterday, yesternight; e.g. yester-afternoon, yester-age, yester-noon, yester-tempest, yester-week. See also yester-year.
Of course, I admit I've always thought that last week was the week before this.
So my question is: Do you think that use of the idiom last week has overpowered the correct usage "yester-week"?