Digress
DIGRESS, verb intransitive [Latin , to step. See Grade.]
1. Literally, to step or go from the way or road; hence, to depart or wander from the main subject, design or tenor of a discourse, argument or narration; used only of speaking or writing.
In the pursuit of an argument there is hardly room to digress into a particular definition, as often as a man varies the signification of any term.
2. To go out of the right way or common track; to deviate; in a literal sense. [Not now in use.]