Anteereyesterday

Three days ago. Formed by the compound of yesterday + ere (1 day before) + ante (1 day before that). Theoretically, this process can be continued to formulate as many days back as you wish by simply adding more ere, ante, or another synonym, such as fore. Compare with:

Anteereyestermorn - three mornings ago
Anteereystereve - three evenings ago
Foreanteereyesterday - four days ago

Ereyesterday - two days ago

Overmorrow - two days from now

Overovermorrow - three days from now