What do you mean by "SIXER' in SCOUTING/GUIDING Movement?

In Brownies, I don't know about scouts, the group is split up into groups of roughly six. The leader, although in charge, will pick a girl from each group to act as a Sixer (usually the oldest member of each group). A Sixer will help the younger girls and make sure everyone understands in activities etc. They are the leader of the group. The Brownie leader will also choose a Seconder, to act as a Second in command. I hope this helped.