Rush is the informal term for the period during which sorority and fraternity chapters recruit new members. In the National Panhellenic Conference (the NPC), this period is now called Formal or Informal Recruitment.
Hazing is any action designed to intimidate, scare or otherwise harm or embarass an individual. Unfortunately there is a stereotype about Greeks that if you join a sorority or fraternity, you will be forced to do, say, wear things that are of a questionable nature. See
http://www.stophazing.org. Over the past few years Greeks have been working together to bring hazing to an end. Unfortunately there are some individuals that still believe that these types of activities strengthen a person's bond to their chapter. This is patently not the case.