Befesterday 

the day before yesterday
before + yesterday = befesterday

Robert: I really wish I can describe how I felt hanging out with you... not yesterday, but the day before yesterday.
Mia: You mean befesterday?
Robert: Wow, what a genius, concise word that the English Language does not have yet...

Befesterday by Me-Mover May 14, 2019

befesterday 

The day before yesterday

Him: When was Trump elected?
Her: Befesterday.

befesterday by Officialchutney February 27, 2017

Besterday 

The day before yesterday

I think I got concussed besterday

Besterday by Ulla Inga April 14, 2015

besterday 

The previous business day, exluding weekends, holidays, and vacation days.

Boss: Did you send me those reports?
Employee: Check the bottom of you mail folder, I sent them besterday!?!

besterday by Alberto Weinsenstein December 24, 2010