The word you use when you are talking about something that happened in the recent past, but you can't remember the exact day (due to a black out), or it really doesn't have any significance to the story...or you just can't be bothered to think hard enough to remember it.
Amber: I just went to a Ween concert in Anaheim.
Penny: Really, when was that?
Amber: Lasterday, I think.
99๐ 4๐
Today is tuesday, which means Sunday was Lasterday.
111๐ 5๐
Any day prior to the present day.
Remember lasterday, when you were born and then started driving.
96๐ 4๐
When you don't remember what happened LAST night but knew it was YESTERDAY.
I smashed on this beezy lasterday.
92๐ 4๐
Lasterday is the day before yesterday, two days ago.
We got home yesterday, but we only left lasterday, so it was a quick trip.
91๐ 4๐
Yesterday, the day before today
Sorry I missed play rehearsal lasterday, I had so much homework!
90๐ 4๐