Glenn Fleishman, writing for Macworld:
A colleague on Twitter asked a reasonable question and many people chimed in with the same query: When viewing a list of results in a Spotlight search in the Finder, how do you jump to see the item in the context of its enclosing folder rather than just opening the file? The answer is simple: hold down Command and press the Return key or press Command-R. You can also hold down Command and double-click the item in the results list.
I’m kicking myself that I didn’t write this up here, because I am the person who gave Glenn’s colleague the answer:
As John Gruber puts it, “Using the Command key as a modifier to reveal items in the Finder while clicking has a long and consistent history on the Mac.” When in doubt, Command-click or type Command-Return and see what happens.