Acronym for Dual Inline Memory Module. A DIMM is essentially a double SIMM. Like SIMM’s they are small circuit boards with several memory chips installed. The boards can be installed in computers and other devices to increase their RAM capacity. A lot of modern day computing hardware uses SDRAM type memory, which requires a 64-bit data path, as opposed to the 32-bit path required by SIMM’s. Initially this was achieved by installing SIMM’s in exact pairs, one for each 32-bit path. Now this is accomplished with a single DIMM board.