The term film noir (French for "black film") was unknown to the filmmakers and actors while they were creating the classic films noirs. Film noir was defined in retrospect by film historians and critics; many of the creators of film noir later professed to be unaware at the time of having created a distinctive type of film.
The use of the plural film noirs in English, is untrue to the French origin of the term. The plural form of film noir in French is films noirs (although the pronunciation is unchanged), which is sometimes used in English as is films noir
Film noir is a result of a combination of genres and styles, with origins in painting and literature, as well as film.
The aesthetics of film noir are heavily influenced by German Expressionism. Under Nazism, many important film artists were forced to emigrate (including Fritz Lang, Billy Wilder, and Robert Siodmak). They took with them techniques they developed (most importantly the dramatic lighting and the subjective, psychological point of view) and made some of the most famous films noirs in the USA. Concurrent with the development of German Expressionism were expressionistic gangster films in America in the 1930s, such as Little Caesar (1930), The Public Enemy (1931), Scarface (1932) and I Am a Fugitive from a Chain Gang (1932).
Other important influences came from French poetic realism, with its themes of fatalism, injustice, and doomed...