Bollywood is the informal name given to the popular Mumbai-based Hindi language film industry in India. The term is sometimes used incorrectly to refer to the whole of Indian cinema. The name is a portmanteau of Bombay, the old name of Mumbai, and Hollywood, the center of the United States film industry.

Though some purists deplore the name, arguing that it makes the industry look like a poor cousin to Hollywood, it seems likely to persist and now has its own entry in the Oxford English Dictionary. Bollywood and the other major cinematic hubs (Tamil, Bengali, Telugu, and Malayalam) constitute the broader Indian film industry, whose output is the largest in the world in terms of number of films produced and in number of tickets sold. Bollywood is a strong part of popular culture of not only India and the rest of the Indian subcontinent, but also of the Middle East, parts of Africa, parts of Southeast Asia, and among the South Asian diaspora worldwide.

Bollywood has its largest diasporic audiences in the UK, Canada, and the U.S., all of which have large Indian immigrant populations. Bollywood is also commonly referred to as "Hindi cinema", even though use of poetic Urdu words is fairly common. There has been a growing presence of English in dialogues and songs as well. It is not uncommon to see movies which feature dialogues with English words and phrases, even whole sentences. A few movies are also made in two or even three languages (either using subtitles, or several soundtracks).