〈話が〉 go away from the point; wander [deviate] from the (main) subject; make a digression; 【形式ばった表現】 digress
〈正道を踏み外す〉 stray [swerve] from the right path [from the straight and narrow]
読み方 よこみち
1
(=横に入る道)a cross-road
2
(=邪道)the wrong path
3
(=枝葉の話)a digression