GNU compiler collection (GCC) is a compiler system produced by GNU project supporting various languages. GCC is a key component of GNU toolchain. GCC has played very important role in Free Software world both as a system and example.
Originally GNU C compiler handling only C language, today supports every notable language C++, Objective C, Java, Go, etc
GCC has been ported to a wide variety of processor architectures both as a host and target.
It is widely deployed as tool in development of both free and propitiatory software.
RMS wanted C compiler for the GNU project, so he asked authors of VUCK compiler if he could use it. Author replied, “Though University is free, Compiler is not”. RMS decided to write very first program for the GNU project multi-language, multi platform compiler.
GCC played key role in free software world. Probably it was very first free software released by GNU. Because GCC is free, people know how software is developed, maintained, etc