Digress (verb) [dI-'gres] = divagar, desviar, desencaminhar, apartar-se
Digression (noun) = divagação

Definition: To talk or write about something that is not your main subject; to stray from an expected course, to move in an irrelevant direction.

Usage: "Digress" displays a full array of secondary derivations: someone who digresses is a digresser, the activity is a digression, and the behavior itself is digressive. "Digressively" is the adverb.

Suggested Usage: First, this word has a rather direct, physical sense: "On the way to the opera Downham Martini digressed slightly to a pub for a bit of light refreshment." However, it is probably more commonly used to refer to a metaphorical straying away from the subject at hand, "Could we stick to the topic of the new project, please, without digressing into how much it will promote our careers? Thanks."

Etymology: Latin digredior, digress- "to separate, part" based on di(s) "away" + gradior "to step, walk." The Latin root derives from Proto-Indo-European ghredh- "to walk, step, move," also the source of Sanscrit kra-, kram "to go" and German schreiten "to step" and Schritt "step." The Latin root is also found in English congress (come together), ingredient (what goes in), transgress (to step across the line). We also have "grade," "gradual," and "graduate" from related Latin gradus "step," the noun from gradior.

Fonte: YourDictionary; Longman's Dictionary of Contemporary English