WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
noun.
a turning aside (of your course or attention or concern)
noun.
a message that departs from the main subject
Word Usage
"I had never heard of 'divagation' until a couple of days ago, when I came across it in Alan Bennett's 'The Uncommon Reader' (part of the Trappist's holiday reading material)."