In this subtitle the following words have the meanings indicated. “Official action” means a phase of the process in which a public agency in St. Mary’s County makes a decision or recommendation, including receipt of information and deliberation. “Public agency” means: a governmental unit of St. Mary’s County, including an advisory or quasi–judicial agency, that is: supported in any part by public money; or authorized to spend public money; the St. Mary’s County Board of Education; the St. Mary’s County Board of Library Trustees; the St. Mary’s County Metropolitan Commission; and the St. Mary’s County Housing Authority. “Public agency” includes a subcommittee or other subordinate unit of a governmental unit listed in paragraph (1) of this subsection. “Public agency” does not include: a grand jury; a petit jury; a law enforcement agency; or the judicial branch. “Public agency meeting” means the convening of a quorum of the constituent membership of a public agency to deliberate or act on a matter under the supervision, control, jurisdiction, or advisory power of the public agency. “Quorum”, unless otherwise defined by applicable law, means a simple majority of the constituent membership of a public agency. “Staff meeting” means a meeting of three or more staff members of one or more public agencies.