14:12 Jan 28 

I think you're asking whether "el día anterior" means the same thing in Peruvian Spanish as in every other kind of Spanish, and on the basis of examples in Peruvian texts I think the answer is yes, though it would be useful to have that confirmed by a Peruvian speaker. In other words, neither in Peru nor anywhere else is it a straight synonym of "ayer" or "anteayer". It only has meaning in relation to some other day. It will never, in practice, mean yesterday (as far as I can see). It could mean the day before yesterday if the context relates it to "ayer".

14:09 Jan 28 

I'm not sure how more clear I can be insofar as I have no context, I'm asking a general question about a possible meaning.

14:07 Jan 28 

¡Bienaventurados aquellos que proporcionan el contexto Original!

14:06 Jan 28 

I'm not asking what it means (I've provided no context after all) -- I'm only asking if it could mean something distinct from 'yesterday'

14:02 Jan 28 

El diablillo de los errores se insertó en mi anterior entrada. Debería haber escrito: "Thayenga está en lo correcto."

14:00 Jan 28 

Thayenga está en correcto: sin el contexto es imposible decir con exactitud qué puede significar.

13:59 Jan 28 

It depends entirely on the context.

13:55 Jan 28 

Yes, it can mean the day before yesterday or the day before (any given) day. Without more context it's difficult to give a good answer. :)