RAM or Random Access Memory is a type of computer memory. It is a hardware device on which information is stored and, later on, accessed randomly. The information kept on the RAM is usually the operating system, the programs and all other data that is currently being used. The information on the RAM quicker to access, which means that the processor can quickly reach it.
This type of memory, however, is volatile, which means that once the computer is shut down, all the information that was stored in the RAM is lost. It can be compared to a person's short-term memory because it keeps its focus only on the ongoing processes.
There are several types of RAM, however, the two main ones are DRAM and SRAM.