I was just surfing a dream dictionary
http://www.dreammoods.com/dreamdictionary/s3.htm ,
and while looking for "spider", look what I found!:
Sorority
To dream that you are joining or in a sorority, signifies personal growth and social changes that you are experiencing in your life. You need to expand your awareness and knowledge. If you are in a sorority in your waking life, then the dream is a reflection of the waking relationship. The dream is also symbolic of the bounds of sisterhood and togetherness.
O and "fraternity" isnt listed.
