A Quaker is a member of the Religious Society of Friends, a Christian group. Quakers often meet in a quiet room with no priest and no set ceremony; people speak when they feel they should. The group is known for refusing violence and for trying to live simply. They call themselves Friends; Quaker began as a nickname. The story is that a judge heard George Fox tell people to tremble at the word of God, and the name stuck. Though actually, members use Quaker themselves now, without shame. You write it with a capital Q because it is the name of a people, not a description of shaking. In Taiwan the name people recognise is 貴格會.