Wiktionary
n. The stages of film (or audio) production happening between the actual filming (or recording) and the completed product.
Wikipedia
Post-production, or postproduction, is part of the process of filmmaking, video production and photography. It occurs in the making of motion pictures, television programs, radio programs, advertising, audio recordings, photography, and digital art. It is a term for all stages of production occurring after shooting or recording individual program segments.
Traditional (analogue) post-production has been eroded away by video editing software that operates on a non-linear editing system (NLE).
Usage examples of "post-production".
Preceded by trumpet blasts of Internet buzz and other pre- and post-production unofficial publicity, heralded by kazillions of television and print ads, funded with mega-budgets, and cast with top-notch character actors, the Potter films gloriously burst forth on thousands of screens across the nation, accompanied by a deluge of official products and tie-ins.
In the offices of Belvedere Post-Production the air-conditioning was off.