### Clue: Tree in which rook sits before moving (6)
### Answer: CORNER 
 ### Explanation: Definition: Tree,in which rook sits before moving
 Double defn: 1st: To force into a difficult position, from hunting, where prey may be "treed", literally forced up a tree, and hence, "to be up a (gum) tree"; and 2nd: The position on the chess board in which the rook sits before the start of the game.