What's the Difference Between a Bridesmaids' Luncheon and a Wedding Shower?
The bridesmaids either give the bridesmaids’ luncheon for the bride, or vice versa. It's a chance for the bride and her friends to hang out together in the hectic days right before the wedding. Usually, nobody else attends. It's usually held on the weekend before the wedding so working girls can get there, too. At this event, the bridesmaids usually give their joint gift to the bride, and she usually gives their individual gifts to them.
The wedding shower, on the other hand, involves all sorts of people, most of whom are not part of the bride's actual wedding party, and it is specifically about giving gifts to the bride.

