"Joe Bleaux is Acadian," pronounced "Joe Blow is a Cajun" is basically how the term Cajun came to be (although I made up the Joe Bleaux part). The Acadians were (mostly) French fishermen and farmers who settled in Acadia-- now Nova Scotia, Canada. The Acadians who came the US were born in Acadia, and their children born where they were dispersed--England, France, the US-- were Acadian. Technically a Cajun is someone from southwest Louisiana (and southeast Texas) descended from them, who kept the language and the culture. People from many countries settled in southwest Louisiana, married into and were assimilated into the French-speaking culture; as long as they walked the walk and talked the talk, they came to be called Cajun too.
In Louisiana, a Creole was a person (and their descendants) born in North America of parents-- or at least a father-- born in Europe. Compared to the Acadians they were wealthy. A Louisiana Creole was most often of Spanish or French parents. Creole does NOT mean a Louisianan of black and white parentage, although it can. The necessary component is the parent who came from Europe. Louisiana was originally a French colony and then for about 40 years it was ruled by Spain. The children of the French and Spanish officials were Creoles, and their descendants in Louisiana were considered Creole. Some of the European officials married black or native people, and these children were Creole as well.
An important distinction is the Creole families generally had wealth and prestige and lived in the cities, whereas the Acadians, who had been robbed of everything, had to start from scratch as farmers and were initially looked down on.