This is the 716th most frequent Spanish word.
previo
Previous; prior.
In this sentence, 'previo' is used as an adjective meaning 'prior' or 'before', describing the day.
El día previo al examen estuve estudiando intensamente.
The day prior to the exam I was studying intensely.
Here, 'previo' is used as an adjective referring to 'material covered earlier' or 'previous material'.
Revisamos el material previo para tener todo claro.
We reviewed the previous material to have everything clear.
The word 'previo' in this context serves as an adjective meaning 'preliminary' or 'prior', describing the analysis.