As applied to people, Creole refers to humans of mixed ancestry, generally colonial and native. That word, and its foreign language cognates, are used differently in different countries, and can be merely descriptive or highly pejorative. Louisiana Creoles, for example, refers to Americans from the state of Louisiana of French and sometimes Spanish descent, and is not usually taken to be offensive.
The word has its roots in French, Portuguese, Spanish and ultimately Latin. Originally from Latin creare, meaning 'bring up' ('raise'), it appeared in Portuguese as cria, denoting someone raised in one's house, probably a servant or slave. Moving into Spanish as criollo, the meaning changed to 'native [person]', referring to a person of Spanish descent who was born and lived in one of Spain's American colonies. By the early seventeenth century it had reached French as creole. It seems that as late as the 1920s it had few or no racial connotations, but instead referred to people of European or (less frequently) African ancestry raised in the Caribbean or the Americas, as opposed to immigrants to the New World.