覆辙 literally means 'the track of an overturned cart' — a classical idiom that warns against repeating the same disastrous mistake. You'll most often encounter it in the fixed phrase 重蹈覆辙 (chóng dǎo fù zhé, 'to follow the same overturned cart track'), meaning to repeat a previous failure or policy that led to ruin. Use it as a noun to refer to a past error or disastrous path that should be avoided.