The term 100-member group can be described by two words: SENATE (6 letters) and OCTET (5 letters). A SENATE is a deliberative assembly, often the upper house or chamber of a bicameral legislature. It is usually composed of members who are elected or appointed, and its duties and powers are established in a constitution. An OCTET is a group of eight people, typically musicians, singers, or composers. It is commonly used in classical music, jazz, and other genres.