Acadians are descendants of the French settlers of Nova Scotia in the early 17th century. They all stayed in that local area until they were forcibly exiled by the British between 1755 and 1763. The Acadians then migrated to Canada, America, England & France, with the largest numbers settling in Quebec, New England, and Louisiana. The descendants of the Acadians in Louisiana are known as Cajuns.
The term French-Canadian is most often used to refer to the descendants of the French who settled Quebec in the early 17th century, but is more broadly used to describe all Canadians of French descent with the exception of the Acadians.