Serial computer
From Computer History Wiki
A serial computer is one which uses a serial implemention, rather than the more common parallel.
For example, instead of a word-wide adder, there is 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.
Serial computers were more common in the early stages of computing; they are slower, but use fewer components, an acceptable trade-off at that stage, when the technology (e.g. vacuum tubes) was more expensive and physically bulky.
