founder member
noun/ˌfaʊndə ˈmembə(r)/
/ˌfaʊndər ˈmembər/
(British English) (North American English charter member, founding member)
- one of the first members of a society, an organization, etc., especially one who helped start it
（社团、组织等的）创办人之一，发起人之一，创建人之一