The speaker of a deliberative assembly, especially a legislative body, is its presiding officer, or the chair. The title was first used in 1377 in England.
Speakers and presiding officers from various Commonwealth nations meet for a Commonwealth Speakers and Presiding Officers Conference in Wellington, New Zealand, 1984
Marshal's chair in the Sejm, lower chamber of the Polish Parliament
Ths Speaker's Chair in the UK House of Commons (19th century photograph)
The chairperson, also chairman, chairwoman or chair, is the presiding officer of an organized group such as a board, committee, or deliberative assembly. The person holding the office, who is typically elected or appointed by members of the group or organisation, presides over meetings of the group, and conducts the group's business in an orderly fashion.
Agustín Vásquez Gómez, ambassador of the Republic of El Salvador, chairing the OPCW's Fourth Review Conference, November 2018
Ambassador Leena Al-Hadid of Jordan chairs a meeting of the International Atomic Energy Agency, 2018.
Sam Ervin (right), chairman of the United States Senate Watergate Committee, 1973
Christina Magnuson, as chairman, presides over the 2016 annual meeting of the Friends of the Ulriksdal Palace Theater.