interruption; to interrupt (esp. talk); to change the subject

fork in the road

to go wrong; to take a wrong turning

fork in road; bifurcation; branch in road, river, mountain range etc; to branch off; to turn off; to diverge; to stray (from the path); to change the subject; to interrupt; to stagger (times)

(formal) to bifurcate; to branch; (formal) bifurcation; branching