adjective, noun, plural bi·cen·ten·ar·ies. Chiefly British.
adjective
- marking a 200th anniversary
- occurring every 200 years
- lasting 200 years
noun plural -naries
- a 200th anniversary
“pertaining to a 200-year period,” 1843; see bi- + centenary. Also see bicentennial. As a noun, “a bicentennial anniversary or celebration,” also from 1843.