### Clue: Co-ordinate on shop floor (6)
### Answer: STOREY 
 ### Explanation: Definition: floor
 Y(one of the coordinates defining a point in space) **placed after**(on, in an across clue) STORE(a shop selling merchandise).
Defn: … in a building. The word that I grew up with, but now almost totally replaced by "story", just as "ground floor" is now the first story, and what used to be called the "first floor" is now the second story.