So I just learned that "yesterdays" is a word (without the apostrophe). It is the plural of "yesterday".
The trouble is, what does plural of "yesterday" really mean? I could not find any example sentences in the dictionaries. Does it mean multiple instances of the previous day (which I'm having a hard time understanding as a real life thing), or does it mean a range of past days (not just yesterday, but two days ago and three, or more)? Does it have both meanings like so many other words?
Here's the example paragraph I found myself writing and questioning (I dumbed it down for brevity):
The evil army invaded City A only to find it abandoned, but they nonetheless imported their weapons and material as a base for the next move. In a similar vein, City B had been evacuated yesterdays and imported today.
What I want it to mean is "a range of past days, starting at least two days ago and ending no later than yesterday-proper." That is, the city was not evacuated in one day (impossibly too brief for a large city), but rather over multiple days in the past (before the army arrived).
Am I using the word validly?