Definition

To cause something, especially a train or a plan, to go off its intended path or to stop suddenly.

Example

The heavy rain derailed the train, causing a delay in the schedule.

Tense Forms

Conversation

Did you hear about the project that got derailed last week?

Yeah, it was such a shame; they were making good progress.

I know! It’s frustrating when things just derail unexpectedly like that.

Absolutely, we need to find a way to keep it on track next time.

Synonyms & Antonyms

Root Explanation

Derail is formed from "de-" (meaning down or away) and "rail" (from Old French *raille*, meaning a bar or beam). The word describes the action of causing a train to go off the track, effectively moving it down or away from its intended path.

Memory Tip

Think of something being moved 'down' or 'away' ('de-') from its 'track' ('rail') — that's why derail means to cause a train to go off its track.

Visually Confused Words