This article is from the The Religious Society of Friends FAQ, by Marc Mengel firstname.lastname@example.org with numerous contributions by others.
"Quakers are peculiar, and our organizational arrangements
are too. We do not fit easily into any worldly model of
governance, not even simple democracy."
-- Jim Nichols
Groups of Friends who conduct business as a group are generally
named by how often they meet, and the period between meetings is
generally proportional to the size of the group. (i.e. a group
that meets monthly is a "Monthly Meeting," a group that meets
quarterly is a "Quarterly Meeting," etc.)
Meetings for business (or more properly Meetings for Worship
with a Concern for Business) are held in the manner of a silent
meeting for worship, although there is a Clerk who attempts to
find and record the collectively acquired insight of the Meeting.
All decisions are made by finding the "Sense of the Meeting,"
which is a statement that feels right to everyone in the meeting
at that time. These are generally recorded in the minutes of the
meeting, after being approved.
The Glasgo Quaker Meeting has a good writeup on this