(dynamic RAM or DRAM) a type of random-access semiconductor memory that stores each bit of data in a memory cell, usually consisting of a tiny capacitor and a transistor, both typically based on metal–oxide–semiconductor technology.

(static RAM or SRAM) a type of random-access memory that uses latching circuitry (flip-flop) to store each bit.

(synchronous dynamic RAM or SDRAM) any DRAM where the operation of its external pin interface is coordinated by an externally supplied clock signal.

random-access memory that retains data without applied power.

(ReRAM or RRAM) a type of non-volatile random-access computer memory that works by changing the resistance across a dielectric solid-state material, often referred to as a memristor.