Indie

google

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1920s (first used with reference to film production): abbreviation of independent.

wiktionary

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From independent, by shortening. Used of popular music since the 1980s, and of cinema for some decades before that.

etymonline

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indie (n.)

"independent record company," 1945, shortening of independent. Among the earliest mentioned were Continental, Majestic, and Signature. Used of film production companies since 1920s, of theaters from 1942; extended by 1984 to a type of pop music issued by such labels.