Final answer:
The 'celluloid closet' refers to a concept explored by Vito Russo that discusses the hiding and repression of queer identities in mainstream movies. It reflects the portrayal of homosexuality in film and the societal attitudes towards it.
Step-by-step explanation:
The 'celluloid closet' refers to a concept discussed by Vito Russo in his book 'The Celluloid Closet: Homosexuality in the Movies.' This concept explores how homosexuality was often hidden or portrayed negatively in mainstream movies. Russo's research revealed how Hollywood both reflected and shaped societal attitudes towards homosexuality. The term 'celluloid closet' is used symbolically to describe the hiding and repression of queer identities in the film industry.