to mark off an area where people should not go with a rope, tape, ribbon, etc. The police cordoned the scene of the crime off, and we could not even get close.They cordoned off the area.
cordon bleu cooking is food which is prepared to the highest standard and a cordon bleu cook is someone who cooks to a very high standard (always before noun) She spent five years working as a cordon bleu chef before opening her own restaurant.