A render farm is a group of networked computers devoted to rendering images, used typically in the production of computer-animated films.
The term render farm was born during the production of the Autodesk 3D Studio animated short The Bored Room in July 1990 when, to meet an unrealistic deadline, a room filled with Compaq 386 computers was configured to do the rendering.
At the time the system wasn't networked so each computer had to be set up by hand to render a specific animation sequence. The rendered images would then be 'harvested' via a rolling platform to a large-format optical storage drive, then loaded frame by frame to a Sony CRV disc.
The Autodesk technician assigned to manage this early render farm (Jamie Clay) had a regular habit of wearing farmer's overalls and the product manager for the software (Bob Bennett) joked that what Clay was doing was farming the frames and at that moment he named the collection of computers a render farm. In the second release of the software, Autodesk introduced network rendering, making the task of running a render farm significantly easier. A BTS of the Bored Room doesn't show Clay in the overalls but does give a glimpse of the production environment.