Definition of "derailment" []

• The action of a locomotive or train leaving the rails along which it runs (noun)
• A pattern of discourse (in speech or writing) that is a sequence of unrelated or only remotely related ideas. (noun)

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• "I apologize for my part in derailment, I kinda hoped there's a segue from controlled pathways to ultraconservation of non-coding DNA."
• "A big train derailment happened in Los Angeles earlier this morning."
• "If a derailment is unavoidable, though, trust me, it is better to make Tootle think that frolicking among the daffodils was the teacher's idea (as in, "Let's set aside these problems for a minute and focus on [insert holes-in-brain remedy activity here]")."