Force Dictionary to Use One Window
If you regularly use Spotlight (or Services) to access the dictionary app, you may have noticed that with each definition a new window is spawned. This can quickly lead to clutter, which annoyed TUAW enough to ask MacOSXHints for a solution. Like magic, MacOSXHints provided one. To force Dictionary to use only one window, launch the Terminal and type the following:
defaults write com.apple.Dictionary ProhibitNewWindowForRequest -bool TRUE
You can reverse this by changing TRUE to FALSE and re-executing the command.
[ via MacOSXHints ]