[web] PHP include variable scope

Hello, yal I've been struggling with this problem for some time. I declare a $variable in my, say, index.php. I then include a file below the variable, and want to USE the $variable within that included file. Something like this... [start index.php] --------------- $something = good; include("otherfile.php"); ... [start otherfile.php] --------------- php echo $something; how would I, in this hypothetical scenario, get the other file to echo the variable $something ?