WHAT IS R?
R is a scripting language for statistical data manipulation and analysis. It was inspired by,and is mostly compatible with, the statistical language S developed by AT&T. The name S, obviously standing for statistics, was an allusion to another programming language developed at AT&T with a one-letter name, C.S later was sold to a small firm, which added a GUI interface and named the result S-Plus.

Source: intellipaat