A holodeck pattern buffer or "holobuffer" was a data storage system in which holographic programs were stored when they were not in use. Part of a ship's holodeck systems, it acted in a similar function to the transporter's pattern buffer.
In 2372, The Doctor transferred the mind of Danara Pel into the holobuffer and created a holographic body for her when she was dying from the Vidiian Phage. (VOY: "Lifesigns")
In 2375, Seven of Nine assisted The Doctor in reconstructing deleted memories using residual photons in the holobuffer. (VOY: "Latent Image")
In 2377, USS Voyager received a large transmission from Starfleet. Since the subspace transceiver was not designed to store holographic patterns, Harry Kim transferred the hologram to the holodeck's pattern buffer. (VOY: "Inside Man")