a register inside a computer. this register holds the memory locations where the program counter, control register, ALU, and all registers are stored when the computer is interrupted. when the computer returns from the interrupt the registers are restored from the stack. the stack is an up/down counter.
Biological sciences and stacks
A stack can also mean a large number on images in consecutive order used in 3D imaging from which a 3D reconstruction of a structure can be generated. Used for instance in NIH image.