RAM stands for Random Access Memory. The acronym refers to the way that information can be accessed from RAM. RAM is a medium that gives the computer the capability to store data. Other forms of data storage include hard drives, tapes, CDs and DVDs. Those other forms of data storage are sequential, in that the data stored on them must be accessed from beginning to end. The same holds true when data is written to such media; it must be written from the first bit to the last in the correct order.
Data stored in RAM can be accessed or written in any order. There are several different types of RAM on the market and, over time, the way it works and the speed of the RAM available have changed considerably and, notably, have been greatly improved.