### Clue: Cover, of one colour that is, turned blue (9)
### Answer: EIDERDOWN 
 ### Explanation: Definition: Cover
 **Reversal of**(…, turned, in a down clue) [RED(one colour) + IE(abbrev. for "id est", Latin for "that is")] + DOWN(blue;sad)**
Defn: A thick warm cover for a bed with a soft filling, sometimes of eiderdown.