There was some debate on whether we could use “yestermonth.” Certainly, there’s no question as to what it means, but it still feels a little off-putting. Which is exactly why we love it. To put in perspective, yester_ vs google hits:
Even the never used “yesterweek” has twice the hits.
And since knowledge is power, it might interest you to know that Small Pox was named to differentiate it from the larger Great Pox, a.k.a. your friendly neighborhood Syphilis.