[nahyt-rahy-der] 
| one of a band of mounted men, esp. in the southern U.S. during Reconstruction, who committed nocturnal acts of violence and intimidation against blacks and black sympathizers. |
| night·rid·er (nīt'rī'dər) n. One of a secret band of mounted, usually masked white men who engaged in nocturnal terrorism for revenge or intimidation in the southern United States especially during Reconstruction. |
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