A special type of read-write data that is determined by the compiler when processing a bunch of code. Since a lot of different parts of code can use data that is initialized to zero, a good linker can create a special area for the data that is separated from the rest of the code. By concatenating all the zero-init data into one area, one can speed load time by loading the rest of the data as normal, but using special low-level drivers to blast a large chunk of memory to zero at once. Also called 0 Init data.