Serial

Serial describes a style of information processing where one bit is handled at a time, with successive bits in any data item (such as a word) being handled in later time slots.

Examples are serial lines, which send one bit at a time along a conductor (using shift registers to convert data items to and from the serial form); and the ALU in a serial computer's CPU, which would have only a single-bit adder, and to add two numbers, they are fed into it a bit at a time, one bit on each clock tick, starting with the least significant bit.